163cm and Weigh 50Kg, Would I Have Enough Fat for the Procedure?

Hello dear!
Thanks for the question and provided information as well.
Fat can be harvest from many areas: arms, abdomen, back, flanks, thighs, etc. Unfortunately, without pictures, it is very difficult to give you a proper answer. 
In general, you need to be physically healthy and at a stable weight, have realistic expectations, be a non-smoker and your BMI needs to be 30 or less. l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)

     There are some rather thin individuals in which you really have to work to get enough fat for the Brazilian buttlift.  Sometimes, the arms, medial thighs, and posterior or lateral thighs along with remaining trunk fat provide enough fat for transfer.  If I cannot get 600 cc or so per buttock, I do not typically offer the procedure.  Find the plastic surgeon with ELITE credentials who performs hundreds of Brazilian buttlifts each year.  Kenneth Hughes, MD Los Angeles, CA