Is the facts enough to break up with her?

Yes.

Am I a asshole for thinking this way?

No.

Could you realistically trust someone that age to be faithful and bartend till close 3 or 4x a week?

Not if I'm considering the information you've given.

What do you think, what do you think you would do?

I value my sanity over my emotions, so I'd break it off with her. Don't give her a "quit this job or I'm leaving" ultimatum or anything, just explain to her that all the pieces of the big picture don't fit right for you.

In the future, try sticking to women who are closer to your own age; a lot of the problems that exist in age gaps aren't ones that can be talked out or compromised on.