How tall should a boy be after puberty if your father is 5ft4 and mother 5ft3 im 13 5ft4?

The average adult male height using the mid-parental method is

(father's height + mother's height) / 2 + 2.1

Therefore: (5'4 /64in +5'3 / 63 in) / 2 + 2.1 = 5ft 8in.