This is completely untrue. Natural tolerance has NOTHING to do with your gender. weight/height/size do have something to do with it, but not everything. I've known tiny girls, such as myself, who have a naturally high tolerance to drugs, as well as large men who have a very low tolerance. It has absolutely NOTHING to do with your gender, and everything to do with your genes and physical make up. Don't listen to this person, they don't know what they're talking about.
This, is also untrue. One pill can be plenty for a first time user, it's also your safest bet since you won't know exactly how much is in one pill, or what a first time user's tolerance is. Just go with one pill to start out with. Buy two just in case she decides she wants more, but start out with one. Remember, you can always take more, but you can't take less.
This one is true

Just give her one pill and have fun. Make sure you have more though, in case she feels she really needs it