If the fifteen year old is ovulating and the 12 year is producing sperm, yes.
It is impossible for a year old girl to become pregnant.
Even a twelve year old can get pregnant if she has sex.
a girl can get pregnant at one year old
Yes, an 8 year old can get pregnant. The youngest birth on record was to a 5 year old girl.
No, definitely not. A 16 year old girl is not considered an adult wheather she is pregnant or not!
Yes, a 50 year old can get a girl pregnant. Men have fathered children at a much older age.
NO, that is not possible.
A thirteen year old girl can get pregnant if she has started ovulating and has unprotected sex.
You shouldn't! But you can.