My girlfriend is always talking about other guys?

Hi there, I am 16 and I love my girlfriend to bits, so much so that whenever there's even a whiff of another guy In the equation I get all jealous. For example, we'd be sitting in the park and a couple of men would walk past and she'd kind of stare and say "woah those guys have nice arms" or something, and then there is just constant posts and comments on facebook to and from her friends and photos she takes on holiday of all these boys and celebrities and models and boys she sees who are really "hot" and how "nice" there bodies are. Now I'm not a total weed, I have a relatively athletic body, but until now I thought my girlfriend didn't really care, and that it was just my personality that she likes. But now I see she's near fixated on body image and that. And it kind of upsets me, I was quite confident with my image until now. Is it normal to feel this way? Because I really don't want to be that "jealous" "clingy" boyfriend. Thankyou for any help.