She said "deal with it"? Ouch. She doesn't care for you much, why are you talking to this girl? I knew a girl that said something similar like that at one point as well, but this was in a rocky patch with a friend from grade school, she ended up dumping him but still talking to me. I don't think it's the same case for you, so I'd just say something like (and I'm going to put a little effort into this): "Why are you being passive aggressive about it? It's your decision to be with who you want, you don't owe me anything. If we can still make a friendship out of this, I would be glad, if not, then I don't need to bother attempting to keep up with you if you're going to act like this just because you know that I have feelings for you(crushing in high school, so maybe just say interested in her instead)." You'll be both considerate, honest, and straight forward. It shows you can move on and forget about her easily if you want, but that you're still willing to be friends if she goes through with it and reconciles with you. I think something like this is your best move.