Why does my girlfriend act like a child.?

My girlfriend is 30 years old and very gorgeous. She is my future wife but i cant stand how immature she is sometimes. She talks like a little girl sometimes and when she speaks to her family in colombia it sounds like a little teenager girl is talking to her father.. daddy this and daddy that. I love her but this places a problem in the affection and bedroom side. She does things for me to show affection but physical .loving affeciton is out of the question because of how she was raised and stuff and we arent married yet. SOmeone explain to me whats the psychology behind her wierdness??? i really think im starting to hate her for it :(