Thank you for your question. It is not a problem to have a lift now, but you may need another surgery after having children as the breasts do change significantly after pregnancy. I hope this helps!
Due to swelling and asymmetric tension the nipple can sometimes be pulled preferentially to one side or the other. As swelling subsides it usually ends up in the desired location.
A breast lift is not a particularly physiologically stressful operation. With clearance from a cardiologist you should be able to have this operation done safely.