Pretty much everyone figures out how to actually socialize, maintain relationships, have new relationships, improve them, and date at high school, MAYBE college at the latest. I'm 30, almost 31. Did I miss the boat on learning that and having a semblance of happiness in my life, and there's no going back.
I've tried it all. I've tried social hobbies, I've tried going out, I've tried putting myself out there. The basics of social skills elude me. I am, at best, a filler friend. I can't see myself being any more than that, and I think it's too late for me to get better.
I think I doomed myself to a life of loneliness, all because of the bad choices I made. The only possible hope I can have is maybe reincarnation is real and I can suck less in the next life.
Others here are being helpful, so I'll just throw my 2 cents that friendships and social life are overrated. I have lots of what I call "close acquaintances" and they're fine people but I always wish they were fine email bots instead. Some people can definitely be happy without friends, dating and all that stuff.