Probably ego.
Maybe this story will make you feel better:
When I was 20 I was in the party scene and getting a lot of pvssy. I met this girl who was visiting from Norway, which I found out was a foreign exchange student. She was supppperrrrr hot, and had everyone's attention. Tightest ass, beautiful lips, sexy face... mmm. We hit it off good, made out some, and she was really digging me. I got her number and we exchanged some texts and sh!t. I got her to agree to meet up with me, so I picked her up, and took her to my house (and had every intention of banging her). We were making out and things got pretty heavy, then she started making some jokes about me being too "old" for her. I knew she was joking/playing hard to get, but for some reason my logic kicked in and I realized I'm 20, and this girl is 17.. still a minor, and illegal to have sex with in my state.
What does Scars do? He chickens out. Takes her home, and cuts contact with her. I did the math and realized by the time she was 18, she would already be back in Norway.
Was I pissed at myself? Yes. I missed out on a good piece of ass.. beautiful peace of ass.
Well, it doesn't end there either.
I find out a few weeks later she is hanging out with (my drummer at the time) and partying with him and my guitarist., and had sex with my drummer.
He went into great detail about it, and it kind of pissed me off. I told him she was young, and that he should watch out.
Nothing ever came of it.
Eventually she went back to Norway, and that was that.
This was my ego at work. I met her first.. She liked ME first.. no, she LOVED me first. She wanted Scars' d!ck.. I could had given it to her.. but didn't.
I know I did the right thing in the end.. but it's still one of the stories I look back on and wonder what would happen if I just did it.. I kinda kick myself for it now.. but oh well.
But to answer your question.. ego.. yes, ego. It will go away with time. There's been a lot of "missed opportunities" I've had... dozens and dozens of girls I know I cold have fvcked but the timing wasn't write, I fvcked up, chickened out, she was too young, or whatever reason..but we all got um and you just have to accept it. As long as you learned a lesson from it, then you're on the right track.
-Scars