You now want more control over things because you feel you are grown up. This can cause conflict with teachers and parents, because you feel they still treat you as a kid You want to be part of the crowd, fitting in with a group of friends, going places and doing things together. Again, this can cause arguments if your parents don't approve of your choice of friends or clothes.
At puberty a boy’s voice will change and become deeper. This is a gradual process while the larynx (voice box) grows, and the vocal cords stretch. The voice may alternate between being squeaky or deep, and is usually known as the voice ‘breaking’. The voice can break any time between the ages of 13 and 16, before eventually settling down.
Sweat glands and testosterone (male hormone) gives the boy a more characteristic male body odor. Underarm and pubic hair are actually scent transmitters. They provide a path for the scent of an oily secretion from the skin in those areas to be radiated through the air.
The bad smell comes from the bacteria which lives in the sweat from under your armpits and groin.