If shes only 19-my guess is she doesnt have many exes.. Young people can be naive, insecure, thinking they can tame a bloke or change him..
It is possible she has grown up and realized that she has to find someone who doesnt need to be changed..many young women learn this lesson the hard way. Some never learn
Was she with any of these exes for long? Did she allow them to walk all over her? If yes, id be worried about her self-esteem. If she does dump you for a bad boy then it is her loss mate. Dont even worry about it. If it happens, it happens..
Youll survive, learn your lesson, move on, meet a great girl. All relationships teach us more about ourselves and what we want and need
enjoy what you two have, dont worry about the what ifs.. As long as shes treating you right-its all good. One strike and shes out though
good luck
"Don't ask a question if you can't handle the answer".