Equal to her friends?

My girlfriend says i am equal to her mates and family and that she wants to get married. Is it selfish that i find it hard to want to get married if i mean as much to her as her mates mean to her? doesnt that just make me one of her mates but closer? Should i rethink my own views about this? I know if i had to choose over the life and death of family or mates i could pick her but it would make the feeling stronger if it was mutual. Has anyone else had this kind of feeling? Any experiences or advise would help me alot thanks.