Ironically had she been a male she could have claimed provocation (the classic defence for burgulars who kill male householders who intercept them) but this loop hole (the gay panic defence: alias the murderers' charter) does not apply to women. It works on the novel basis that if a man thinks he may be sexually assaulted by a homosexual male he will lose control and may kill the alleged attacker. If a woman thinks she is going to be raped by a man or sexually assualted by a woman she does not have a similar defence other than pleading she was acting in self defence. The latter is harder to prove, for some reason.
In this case I am rather suprised that she wasn't given an additional penalty for what, on the surface at least, seems to have homophobia as a motivating factor.