Follow up:
In my younger years, I could identity with your uncertainty. I can only speak from my personal experience, but hopefully, it'll resonate in some way.
There was a time when I used to jokingly wonder if I'd unknowingly made some deal with the devil. After my move from a smaller town to a larger city (less than 30 minutes away) it was almost surreal.
It's not that I moved to this larger city arriving with a low self-esteem. It was more like, I knew from past experiences how 'high of a level' I could expect to go with future women. I soon discovered that I had set limits on myself where they didn't exist through the eyes of women.
In fact, at first it was very awkward. I'd look around and see guy's with better wit, nicer cars, more "in the know" and yet women (that I believed were above my stature) was focusing on me and not them. It didn't make sense. Because I wasn't accustomed to this, I'd kind of think to myself "what's wrong with these women.?" Again, it's not a self-esteem issue. It was more to what I'd been accustomed to getting... and now, I was getting the the types that once seemed unattainable.
I hope that you don't make my mistake. The biggest obstacle I had was myself. Have there been other obstacles? Sure. If she lives at home, you are up against their parents approval. Also, try to stay away from women that have a lot of gay male friends. I'm totally cool with gay's, but they can be competitive for a woman's attention - if she starts to develop a romantic interest in a man.
Bottom line: never be hostage to the approval of others. Obviously, with this gal, you have a formula that works. Keep that going. If she does something out of line, do not go overboard with the disapproval, but do not take things lying down either. In other words, do not make concessions because you think she's out of your league. Treat her as you'd treat any other gal.