Although advances are being made in the field every day, we still don't know everything there is to know about autism. Right now, a person can be diagnosed as being on the autism spectrum, which scales autism and related conditions under one big umbrella.

The autism spectrum records a series of disorders characterized by difficulty communicating and difficulty interacting with others. Back in the day, for most people, being autistic meant being like Dustin Hoffman's character in "Rain Man."

Now, doctors, experts, and people on the spectrum themselves are redefining what it means to have an ASD (autism spectrum disorder).

While most people with autism are diagnosed in early childhood when language and socialization skills are developing, parents often notice that certain developmental markers aren't being met (speaking, making eye contact, smiling), and this leads them to an eventual diagnosis.

But just because you aren't diagnosed as having autism as a child, that doesn't mean you can never be diagnosed. Thanks to continued research in the field, we're becoming more understanding of ASD and realizing that some people with these "quirks" may actually be somewhere on the spectrum.

If you have ever wondered "Am I autistic?" we've gathered 17 symptoms and signs of autism that could indicate you share behaviors with people commonly diagnosed.

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I spoke with Dr. Wendela Whitcomb Marsh about these symptoms and signs. Marsh is an autism expert specializing in evaluating, counseling, and coaching autistic adults.

Hopefully, this list won't just serve as a checklist to help you figure out if you may be on the autism spectrum, but also as a guide to helping you better understand what life and its struggles are like for people who live with ASD.

"Many people with high-functioning autism, also called Asperger’s, go through school without ever being diagnosed," Dr. Marsh says.

"If you think this might be you and you want a diagnosis, go online and find someone in your area who specializes in autistic adult assessment. Sometimes, just knowing can be a tremendous relief and explain so much that you always wondered about."

17 Signs You’re on the Autism Spectrum

1. You avoid eye contact.

For people with autism, making eye contact during conversation can be difficult. For some, this means making no eye contact at all; for others, it can mean making too much eye contact.

2. You're overly clumsy.

It might sound strange, but it's a symptom of being on the autism spectrum. If you find yourself constantly walking into things, you might be autistic.

3. Common expressions are confusing.

For some people on the spectrum, a phrase like "it's raining cats and dogs" might be something they take literally. They have a hard time understanding these less-than-logical turns of phrase.

Dr. Marsh adds, "You found it difficult to understand humor that relies on sarcasm, puns, or figures of speech, although as an adult you may have learned to understand these the way someone else might learn a foreign language."

4. You can't handle even a minor change.

A person with autism is often a slave to their routine. A change, no matter how small, can totally set them off.

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5. You prefer to be alone.

While they may be totally friendly, at the end of the day, someone with autism may prefer their own company to that of anyone else's. They aren't anti-social; rather, social interaction is just confusing, draining, and hard.

6. You don't seem to understand feelings.

A person on the autism spectrum can understand what emotions are in theory, but they have a hard time putting that knowledge to work in real-time. This can lead to awkward or upsetting interactions.

Dr. Marsh says, "You have successfully learned to imitate and engage in 'small talk' through observation, but you find yourself unable to converse about anything personal, emotional, or in-depth."

7. You're extremely sound- or light-sensitive.

It's not just lights and sounds, either; for some people on the autism spectrum, even textures can be so abhorrent that it throws off their entire day.

8. You don't recognize sarcasm.

Much like the inability to understand a colloquialism, a person on the spectrum may not understand jokes or sarcasm. They require a level of out-of-the-box thinking that is hard for a person on the spectrum to process in real-time.

9. You practice rituals.

A person on the spectrum has routines and rituals that are sacred. It can be something as simple as the way they get ready in the morning or as elaborate as the way they keep their home each day.

Friends and family call it a quirk, but it might be one of the signs of autism.

10. You repeat words or phrases.

A person on the spectrum can get caught in a loop of repeating one word or phrase. Pay attention to your own syntax and see if this symptom applies to you.

11. You have fussy eating habits.

Sensitivities to light, sound, and textures are very common to people on the spectrum, but it doesn't stop there. For people on the spectrum, eating can be tricky or impossible for them to do without their own particular way of handling and eating food.

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12. You have specific and niche interests.

We all have our own interests and hobbies, and people with autism have them, too, but they are intensely focused on them, usually to the exclusion of everything else. Common examples can be anything from a fascination with 1970s Italian furniture makers to being an expert on all things train-related.

13. You have depression or anxiety.

Many people suffer from depression and/or anxiety, but for people on the spectrum, the comorbidity of these conditions is more common. If you're suffering from one of these conditions and other symptoms here apply to you, you may want to consult a doctor about autism.

14. You experience physical ticks.

In addition to verbal tics prominently featuring repetition, a person with autism might have their own physical ticks, too. This is a common symptom.

15. You have a tendency to monologue.

People with autism have a tough time interacting with others. Having a conversation is difficult for them at times, usually because they don't know when to speak, when to ask questions, or do other things that people often take for granted.

"You can lecture at length on topics of interest to you, but you freeze up when confronted with making 'small talk' or responding to another person’s questions," says Dr. Marsh.

16. You want more friends but don't know how.

There's a common misconception that people with autism don't like people, but that's just not the case. People with autism really want to have close friends, they just don't know how.

Dr. Marsh says that "If you marveled at how other kids could make friends so easily, but you didn’t know how," this could be a sign of autism.

17. You're lactose intolerant.

Random much? But yes, it's true. Recent studies have shown that there's more of a connection between lactose intolerance and people with autism.

If you're lactose intolerant and any of the other symptoms sound like you, you might want to consider reaching out to an autism specialist.

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Rebecca Jane Stokes is a freelance writer and the former Senior Editor of Pop Culture at Newsweek with a passion for lifestyle, geek news, and true crime.