Is it wrong that i am sleeping with my girlfriend but no at 17?

NO Dude, what you are doing is the smartest way to go. Having with her will back fire because lets say you do, your going to feel awkward in the end knowing you had and than maybe she will be confused (which girls do) Then the doubts will be BOTH in your head. I'm sorry to hear she lost her mother, My respects to you BRO that you are there for her. Let the healing begin first let her understand what is going on and let her know you are just there for her and time will tell. Listen to your conscience rather than someone else like our friends. God Bless.