It is strange, she is aware the world of gaming isn't for women as it stands. My own reaction has always been, well, it isn't for me then. Hers is different. Her reaction is, she isn't right and the gamers are.
And the other option is that rather than conforming to the gaming world, women can work to change the gaming world and make it more suitable for women.
But if all the women transition to blend in themselves, there will be no women left to fight the fight, and no women left to fight it for.
It's sad that she feels she needs to change herself as opposed to changing the world. With her interest in programming, she could do something really special in the gaming industry.
I would encourage her to mix with other girls interested in tech and remind her that if she has to overhaul her whole identity to fit into a group, the group doesn't sound like a very tolerant place to be.
I guess she's too young for many of the classic lesbian movies/shows, but I would try to find some lesbian things to watch with her (for fun, obviously, not as a lesson!) - it might help to broaden her view of what a lesbian looks like. The US teen show Faking It is pretty good for a positive depiction of lesbianism, IMO.