I think is just they're both are very likeable person/personalities and very down to earth as well, so it's easy for them to get along and become close and comfortable around each other that is not hard for them to be touchy than normally.
They are still on the getting to know, getting along stages. They're still very young so they have plenty of time to think of real relationship or commitment to one person, let them enjoy themselves as is and if doesn't work out, at least they will have forever friends.