Hi ghiblisirel. I can totally understand your confusion, I am also autistic and I struggled with this a lot when I was younger.
The good news is, physical attraction is only one form of attraction and only one of the things that matter when looking for a potential partner. The reason this is good news is because someone being physically attractive but not interested in you isn't a loss - there are going to be tons of other people you find attractive, AND, you don't know if you'd even be attracted to that person on a personal level once you get to know them. An attractive stranger on the street might not be someone you want to date. Looks only go so far, but personality, common interests, shared values, etc. are all even more important than someone's looks. Attraction is something that builds as you get to know someone: sometimes someone you're attracted to initially ends up being not so nice and that attraction is gone; and sometimes you aren't immediately attracted to someone but as you get to know them, the attraction grows. All that to say... there's a lot more to building a relationship than just physical attraction, and you're not missing out on anything if someone you don't know but find physically attracted is taken or not interested.
That being said, I want to ask, what are you looking for specifically? I hear you say you don't want to fall behind socially more than you already have. Is this the reason you want to date? I ask because plenty of people in their 20s have little to no dating experience and that's normal and okay. It's something you should do on your own time when you feel ready for it, not based on society's pressure or expectations.
We do have a series that is super helpful for autistic folks looking for help navigating dating. You can find it here:
A Little Help From One Autistic Person to Another
The first article in the series, "How Do I Tell If Someone Is Into Me?", is a wonderful place to start. Give that (and however many more pieces from the series) a read and let us know if any questions come up. <3