I dated an 18 year old over the summer (i was 21 at the time) and it got weird. Her opinions on many things were either very ignorant or nonexistent. She was beautiful, but it was very difficult for me to hold a conversation with her that interested the both of us. I'll admit however, that i did attempt to 'dumb' it down for a good week for no reason other than the prospect of making sweet, sweet love. Its difficult dating someone still in their teens because they have such little experience in the real world, that really unless its booze or music, there is nothing to talk about.