I don’t think this is a weird question at all! And this is what’s great about talking science – there aren’t really any weird questions, especially when it comes to how humans function.
I’m sure the other scientists will weigh in, but I can talk about how puberty works from the perspective of the brain. In humans, puberty is the process of transitioning to adulthood, usually for purposes of reproduction. A part of the brain releases a few hormones that have effects all over your body. As a result of these hormones, everyone tends to grow hair in new places, the sex organs start to change and develop, and people usually go through growth spurts.
Puberty can be a confusing time, because your own body changes dramatically in a matter of a few months to a couple of years. And some people enter puberty before others – females tend to go through puberty before males. All of this affects your brain, too! Your brain goes through interesting changes as it tries to regulate the new things happening all over your body, which can mean that your mood changes a little more quickly than you’re used to. All of these things are normal, and everyone goes through puberty in their own way.
Puberty has tremendous effects on systems of genes that are expressed.
One of the coolest things about biology to me is how each of our cells has the same DNA in it, and yet there are signals that tell an egg and sperm that have merged to develop a brain, heart, liver, lungs. That there are signals that change our bodies from infants into little kids, and from little kids into pre-teens, and from pre-teens into teenagers, and from teenagers into adults. There are several changes in which genes are turned on and how high they are turned on at every stage in development.
While we understand large-scale changes – huge differences in the amounts and types of hormones our body’s make – we still are trying to understand all the differences that occur as we develop (and then what happens as we age).