You are going to cause me competition !
Anyway I have partially the same way to see things as you do.
However I did already have a first love (still often thinking of her) ; and I also did twice date girls I
wasn't completely into. In both cases, it wasn't worth it. It's more frustration at the end than benefits in the beginning.
The first time was for the wrong reason: forgetting the person I still think of.
The second time was more out of curiosity: what if the spark comes
after the first meetings? The spark never came for me. It did work for a friend of mine though, he tried the same thing.
I won't even start about one night stands, never done that but I think my mind won't accept it. Maybe if I get drunk, but that's just as rare as a reliable government in Belgium.
Anyway after that, I made a promise that's a bit like yours.
However though there's no need to look like your ...English...major.. or whatever. Minds do change, so if one day you're like "Frost it, I'll date and see where it goes", so be it. It's not your promise that rules you, you're allowed to cancel it when you want it. I'm not pushing you to jump on any train though! I'm just saying having a promise is nice, but it's not like a sentimental movie everyone's watching, only you are aware of the promise you talk about.
So, you actually may want to say to your "potential her" about your promise, it might filter out those who really want you from those who want your genitals.
Stick with it but don't let it control you.
I'm 21.3333 years old since 2 days and male since forever.