Guy Problem please help?

I have a friend and both of us knew this guy (Rob) we were both equally friends with him and we sometimes hung out with him at school. I really like him as more than a friend, and just yesterday he asked out my friend. She said no because her parents wont let her date until shes 17 but I thought that he liked me but I guess not. What if he askes me out now can I go out with him or since my friend likes him does this mean i cant. Also neither one of us had his number and he asked her out over text so how did she get his number. Please share your thoughts on what i should do.