I (15m) wish I could be closer to this girl I know (15f) but don’t know what to change within myself

r/

I (15m) have tried to have romantic connections with people who’ve been interested in me, but I can never make it work. I’ve been told that people I know are attracted to/interested in me, i’ve become relatively popular recently and i’ve been flirted with.
But when people try to have any kind of relationship with me I struggle to put effort in.

This one girl (15m) started talking to me more and did so for a while. She complimented me a lot, kept me in the loop, and just wanted to talk to me all the time. She cleared up claims that she’d had sex with her ex to me even when it was completely unrelated and she didn’t have to, which is what first made me think she might be interested in me. I was talking to her in school all the time, and it seemed like we could have something.

But it was really only her putting in much effort. I couldn’t take action. Eventually she stopped talking to me that often.
People expect me to be a certain way because I hang out with popular people and take drugs and go to things. I’m way better looking and better dressed than I was a couple years ago. I don’t get made fun of as much.
But people have forgotten that i’m still cripplingly anxious and insecure due to my past experiences and my autism. I have a hard time starting conversations with people and holding connections because I push them away by being awkward and terrified.

How can I change this? What can I do to show her and other people in my life that I am interested and do care? I am not a cold person at all, and I hate how I manage to come off that way.

Thx a lot for any advice 🙏

TL;DR: I want to get closer to this girl I know but I have to change in order to be able to make a connection with people, but i’m not sure how.