每日吃瓜

Hi
I am brand new to bonsai (and to this forum).
I have a small Acacia Erubescens. It's 3 years old.

I am wondering at what stage I begin to defoliate or prune it. It's very leafy at the top already. I've attached a picture. I'm certain this is a very novice question, but would appreciate any guidance.

Thanks!
Daniel

Let it grow for at least a year before you start to work on it.

Thank you!