Are you in the same class as these kids? "Autistic" can cover anyone from me to the kids mum used to teach & the kids mum used to teach had a lot of additional needs, they were all in the same class and they were not as grown up as an NT at that age.
Either way, autistic people are young for our age socially, old for our age intellectually. This is social stuff. So you have leeway although I'd try to make friends with people in your class (ideally other autistic people).
The real rule is: your actual friends should be your peers. This age group expands as you're older but if you're still at school, it's your classmates, people in after school clubs with you and people your age in your neighbourhood. If you're still in school, unless they fit into the first 2 categories, make them people who are 1-2 years different to you.
For dating, yeah strictly date 17/18 year olds. Dating is different because you can do more stuff with your boyfriend or girlfriend than with your friend.
I'm saying actual friends because mentorship is a thing. A mentor should be someone like: family member, friend of family member, teacher, babysitter. Just because we have different rules on friendship, doesn't mean 'don't be around anyone over 18' or 'don't be around anyone under 14'. That is silly. It's just that the older person should know proper boundaries: don't watch horror movies with a younger sibling, don't teach a 2 year old to swear, don't talk about nsfw stuff with an older person unless you're asking for safety advice.
Online world has changed since I was a teen & it annoys me. And it makes me feel ashamed as it was my generation that did it. When I was 16, I had online mentors. They would give life advice and be open about how they were a lot older. Nothing untoward ever happened. Everything was PG rated. There was another kind of adult, usually a guy, who would hang out in a chat room/Craigslist being a creep. Kids/teens were warned to not talk to this kind of adult and rightly so because he would want to harm kids/teens.
Nowadays, there's an in between category: people who don't really mean any harm and aren't actual creeps but who have teens on their follower lists on social media and who will share NSFW content or info about themselves. It's creepy and I don't blame Gen Z for saying 'DNI if over 18' because people are sharing way too much.
If you're young & autistic or for anyone under 18, I would say: don't post your address, don't post your school name, don't post your full name. Block anyone who knows your age & is prepared to talk about inappropriate stuff with you on their TL. Don't talk about inappropriate stuff online. If you live in a city like London, post 'London' as your address rather than 'Spitalfields', if you live in a town then post 'Yorkshire' rather than 'Malton' (cities are relatively anonymous compared to towns).
I might be taking it too far but on here I've decided to go the route of: no contemporary/party politics, no sports, no NSFW info, no swearing, trying not to get angry with people/in general, don't meet up with people irl, don't give private info. That means I don't care who reads my blog. In real life I'm an adult now, so I don't make friends with anyone who's a teen but if my nephew/niece asks for advice, I'll advise them.