Ugh...the yuck...the idea is I guess that you get attention from older guys means you are better somehow...I remember this from when I was in High School. And that was a long time ago, but, its kinda sick for an older guy to take an interest in a much younger girl and its all about sex...so, she shouldn't fool herself into thinking.
Those kind of rel. leave the girl heartbroken, used, and confused. And worse yet, pregnant I mean, it still happens, right?
Your friend is going to make up her own mind, but maybe you can forward stuff to her about what sexual predators really are, and how they operate, there is plenty out there about it.