Hmm, she knew you were a virgin, and still slept with you knowing she was seeing another guy? In my opinion, and maybe I'm old fashioned, but that wasn't cool. Your first time is supposed to be special, she probably should have told you this was just a casual thing before anything happened. Not judging anyone, but that wasn't a kind thing for her to do. Your first time is a pretty big deal, and it sucks that it ended like this.

I was going to say this, but I didn't want to be a downer on this sub, it's usually a fairly positive place.

But yeah, I think the goal in life should be to be the best version of yourself that you can.

You will very rarely achieve all of your dreams, or do all of the things that you ever wanted, because that's unfortunately not how life works most of the time, but you can learn to accept who you are and what you have achieved, given your capabilities and limitations.