Is it possible to become very social over the course of a year? Late twenties lonely

Ptsd has resulted in me being quite introverted over the last few years. Previously I was quite social.

I’m afraid I’ve lost those skills. I’m not sure how to become social as a person in late twenties. Feels like everyone’s in their group already and I want one!! I want to return to socializing a bunch. I haven’t had birthday parties for years because I only live near two friends.

Is it possible to make enough friends to have a big party a year from now? Any tips!!!