I'm 15 and i need relationship advice?

i'm 15 and i just started datin a girl whos older, shes 18 anyway we recently became ually active and weve discussed what we like and all that and she keeps bringing up doggie style which i was totally into but she says she wont do unless she can do it too , i really like her and i dont want to make her mad but it doesnt feel good when she puts it inside me , she lets me do her sometimes but i dont wont to do the other thing anymore . any suggestions please ?