what are the effects of sex at an early age on girls? there are some studies that show teens becoming delinquent more ofter if the have sex at an early age and such but are there any physical effects? how about mentally?

The reason I want to know is I am a single father and I have a 12 yo daughter who has recently become interested in sex (we are a very open family so we talk about that sort of stuff). she ashed me to take her virginity but I don't know if it is too soon, but she keeps asking me to do it and I don't want to disappoint her.

Any help would be appreciated.