Beyond telling your parents, the process you and your family will have to go through to obtain a diagnosis really depends on quite a few factors. First, there's the opinion of your GP. Although you can bypass a referral (with some insurance plans) and see a psychiatrist or neuropsychologist directly, I initially took that route and it didn't go very well. Professionals qualified to assess an older child/adult for autism are pretty hard to find if you aren't intimately experienced with the labyrinth that is the health care system. And beyond that, not everyone who can assess you should assess you. It's the kind of thing you want to be picky about, and a GP will help you avoid running in circles (taking for granted that they're a good doctor).
Depending on their preferences, your GP might send you to any number of places (neurologist, psychologist, etc). The kind of tests you take will vary depending on where you go. After you have options, though, there's also the cost. The most common option, neuropsychological assessments, can be really expensive. If your family isn't in a good position financially or your insurance plan doesn't cover it, you'll have to find some other source to evaluate you. I know that many psychologists are qualified to assess, but it's a toss of a coin whether they'll be able to recognize less obvious cases, especially if you're female. It's important to find the most qualified person.
All the same, the first step that I would recommend, regardless of your situation, is to talk to a good doctor. Since you're still in pediatrics, they should have established connections with a practice that can assess autism. They can help you find the right means to be tested and get you in faster, too.
There's a lot of uncertainty because the process is different for everyone, but it's worth it, no matter how unnerving it can be. I was shaking the first time I told a doctor about my symptoms, but the people in these fields are often really kind. Just remember that the benefits of a diagnosis are worth it. Until then, continue to read up on autism. You might have to self-advocate, which is scary, but I've found that doctors actually appreciate it. Good luck!
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I have not the kind affections of a pigeon. - Ralph Waldo Emerson