This makes sense to me from my experience. When I was around 18 a lot of people told stories of all the drinking (and sex) they did. I felt quite some pressure

This makes sense to me from my experience. When I was around 18 a lot of people told stories of all the drinking (and sex) they did. I felt quite some pressure to drink more because of that. Later I found out that a lot of these stories were vastly exaggerated. It's pretty sad that people feel the need to brag about destructive behavior like doing but that's the way it is.