Yeah, I've noticed this too. Some of the women I know that are quite attractive now at 22-27 were very awkward-looking at 15-17, which is the age range when all reasonably fit girls are supposed to be attractive. While some of the hotties from high school look old and washed up, even at just 25.
Nah, I know what he's talking about. A lot of girls in high school are lanky or not entirely busty, and when girls "break out" at 14 or 15 that's the hot look for them to have. Those girls very often burn out or don't worry so much about maintaining their looks, while the girls who were awkward-looking grew into themselves and suddenly turned very lovely.