#120859
Ever ask a doctor and get your testosterone/hormones tested? Start there.
It's likely genetic. It doesn't matter what your brother looks like. Some men just can't grow facial hair or it takes forever. Some have to shave every day. Others can get away with every few days or once a week. Some men are way too hairy..back and chest and other guys naturally don't have it.
Did your voice change at all since you were 10? You can't completely sound like a little kid. Some guys don't have deep voices.