I am 21 and have had a both my hips reconstructed. Will a this hip reconstruction affect childbirth?

Possibly. As long as your hips can move into the correct position for a vaginal delivery, it won't be a problem.
It depends. When giving birth, the symphysis pubis (the joint in the middle of the front of your pelvis) has to widen and the sacroiiac joints (the joints on either side of your sacrum or tail bone) have to relax to allow the birth canal to open enough for the baby to pass through. If these structures have not been involved in your pelvic reconstruction, you should not have a problem.