Why do Random older guys keep adding me on Facebook!?

[Lucy]

Everytime I log onto facebook, I have about 5 friend requests from friends of friends of friends who are about 18+ im 14, one guy said he wouldn't mind dating me and that he would love to bang me he is 20 and he knows im 14! and they all say its a random add then ask for my number and say that Im fit and I don't look my age I look about 18, Its soo weird how all of a sudden random guys add me this happen to anyone else?
Its started happening when I uploaded a new photo of me which I think is my best photo on facebook, I havnt updated my profile picture in a while and look good on this photo
for that person who said "you probably look like a whore on your profile pic" I don't at all, its just a picture of my face and im smiling