I wish I had something cheerful to tell you, but I don't.

There's no easy way to fix this but if left alone, it will just get worse over time. You want to break this pattern NOW! while you're still young. AvPd tends to block people from doing things and having experiences that are normal for their age. That's bad enough in itself, but many of these experiences also have an aspect of social initiation to them. As in, you're expected to have undergone them in a certain general time frame, and not to have done so will be considered weird by potential friends & mates. Their negative reactions will then trigger your negative feelings, which will make you want to withdraw even more, and thus the vicious circle is set in motion...

So what can you do? Check out a wide variety of different groups, settings, and sub-cultures. As much as you can, try to let go of value judgements, and focus only on whether or not you feel comfortable with them, or at least less uncomfortable than usual. Once you find one or two groups you at least sort of flow with, then take them seriously. WORK at fitting in like it was school or a job. Try to become a better member of the group by whatever criteria are in effect.

It won't be easy, but you're too young to give up and accept defeat. Your fate is not yet written,
so don't act as if it is.