I'm 16 when will my voice change? i have body hair, longer penis, im building some muscle, but my voice is still high like a child! why?!

Yes it will: You will first experience deepening in your voice at times, so you would be having both child and adult voices, after a while the adult voice takes over and be your own characteristic voice,

Soon: Having started puberty, a change in voice is not long in coming. Meanwhile, you may be able to coax out some deeper tones with singing or voice lessons; at the least you will learn to project your voice with authority. Best wishes.