I need real help, I'm wasting my youth?

I know this sounds superficial, but to me it's heartbreaking. I'm a loser. I'm so shy that I can't even function. I'm a girl in my 20s and I'm wasting my youth away. Never really been with a guy in that way, can't make friends, and I've hated myself for many years. I've only recently realized that all those years of people saying "you're pretty" weren't complete lies, and I actually am kind of cute. But I always look like I got dressed in the dark, and I'm wasting an opportunity to have fun. I just want to have a little bit of fun in my early 20s. It's not fair to miss out on what could be happening because I'm so shy and don't know how to socialize or dress. I would be really grateful for any advice at all.