um all your units are messed up.
if you are 5"3 and want to become 5"9 that is 6 inches.
I don't think this would look good on a girl.
you will have lots of scars because all surgery has scars.
and you will need to lengthen 15 cm which would probably exceed the 10% to 15% safe lengthening limit.
girls naturally have shorter upper bodies. you might look really weird after you get this much lengthening.
and yes readrothbard I will internet slap you if you comment with your rubbish of 20% being the safe limit. it is not and never will be.
are u really buying this crap? She wants to be a model and do at least 4 inches, that's at least 3 years of recovery and 21 is too old for a model to start a career, plus lets not forget modeling is about proportions, arms of a 5'2 girl on a a 5'8 body with legs of a 6'0, imagine that, and going under all this stress, she'll probably look older than a 21 years old female, and doctors don't accept under 18 for cosmetic purposes, oh and I forgot u have to be very special to be a model at 5'8
I may be harsh, but I'm telling you the truth,consider something else if u're good looking, go for acting or something else, but the chances of you being a model are the same as being hit by a lightning after you win the jackpot in africa