Hi!
What if when new players run the game for the first time, they get this question:
Are you a boy or a girl?
They select one option, if they pick boy, they get the free boy skin, if girl, the free girl skin.
Yea, its a little change, but it can make new people use the correct skin based on their gender, instead of getting it on a store.
Of course you can change it anytime in the shop!