I am quite new to asexuality, so take my opinion with a grain of salt (is it the right expression? in other words with a bit of caution... English phraseologisms are not my thing). Firstly, I do not think she is a very nice person to be around, sounds a bit toxic to me. Different people have different ways of expressing themselves, different topics to discuss and it seems that she is just not your kind of people and doesn't really fit in in that group. An asexual person can have sex, can enjoy sex, although not sure what exactly it is called, but it certainly can be a part of asexuality, as I gather the main trait of an asexual is the absence of sexual attraction, and at times it can be difficult to identify. Nevertheless, please, do not invalidate what she considers herself to be. It is her business and her right. It sounds to me something like "You just haven't found the right person yet". Having said all that, you have absolutely all the right to tell her that you...