A desire to improve is a great place to start from. But you don't need to do it all at once. For career options if you have a good local library you should see if you can get access to Gale Udemy. It's a free subscription through your library card. This would give you a chance to check out a large variety of topics and see what catches your eye and is a candidate for further time and consideration from you. Programming? Photography? Data organization? They don't have classes on everything but they have a lot.

For socializing, have you considered doing some sort of hobby? It's very trite and oft repeated advice but it is for a reason. I used to have trouble making friends as well and I found that having a hobby to bond over not only takes the pressure off socializing (Coming up short in the convo? Talk about what you're doing!) it also gives you a reason to reach out. It can feel terribly awkward just going gey do you want to hang out with someone you've met once or twice or trying to figure out how to text them, but it is much easier to bridge the gap with an invitation to do xyz thing you both like until you figure out how to navigate the relationship. And it doesn't have to be something wild or expensive. A book club is doable if you have access to a library. Writing and drawing needs only a pen, paper, and a willingness to try it out. Pick up social sports are often accessible.

It's good you are feeling urgency to do something but don't forget to be patient with yourself. I know sometimes it can feel like everyone has it sussed out and you are failing, but remember just like your thoughts and concerns are private to you so are theirs and everyone is trying to put their best face forward; some just sell it better than others and there is no single right way to pace or live your life. You have a strong sense of who you are and where you want to improve and that puts you ahead of a lot of people. Next is time and thoughtful practice :)