You don't admit the fear. Or at least I didn't. To write this I've got only my own solipsistic adolescence to go on. Although I spent 20 years or so teaching adolescents, I don't know if they felt much like I did. They didn't tell me.
Adolescence is too private to be shared.
That's why teenage boys grunt at their parents. Most teenage boys don't want adults in on their world. They wouldn't understand. And if they did understand, it would be worse. The game would be up.