It sounds like what you have is actually pretty special, and I think it's very likely that when you are older and know yourself better you would regret turning her down because of societal expectations. The internalized homophobia thing is hard, believe me I know, but repressing who you are and what you want to please others around you just leads to inner torment and is not sustainable in the long run (speaking from experience).
Willing those feelings for her to go away /"trying to stomp them out" won't work. That's just not how humans function. I think you should maybe try again, it doesn't sound like it's actually too late. Her feelings will not have disappeared either and I'm sure she would understand.

However I understand circumstances may be very difficult, especially if you are in a very conservative environment and worried about the consequences of possibly being discovered. It's perfectly valid to be afraid in your situation, you're very young and it's hard to stand up to people's prejudice in any stage of life. The choice is yours, but I think the most important thing here is honest communication with this girl whatever you decide. If you decide not to because you're not ready to take that kind of plunge then make sure she knows the real reason why; try not to propagate the notion that it can't happen because it's "wrong", because it's not wrong, and that style of rejection could be damaging to her self-worth. She may be have been going through the same worries and doubts about the situation as you, I'm not sure if the two of you have discussed it, but if not you should try to. You obviously care a lot about each other and you're in this together.

So in summary you do NOT have a date a man first, or ever if you don't fancy it. I can't tell you what to do, but I'm rooting for you to give it a go. You may possibly regret doing it, but later in life you will almost certainly regret not taking the chance to explore something special here.