I don't know about "most cougars" typically going for guys over 25. I can only speak for myself. I prefer guys 25 and under. It does depend on the person, of course, but I'm just not usually attracted to many guys much over that age range. And to answer your question directly, I would have no problem with a 19 yo either as long as he is mature and respectful and like HC said, the chemistry of course has to be there!