Seems normal to me. Mess around = woohoo for teens. You can have teens mess around, then look at the sim stat counter in the simology panel and see that it counts as woohoo and makes the number go up every time they do it.
It doesn't really bother me that much because I do consider it to be the teen version of woohoo and the moodlet that young adults and above get for "First Woohoo" between two new partners doesn't really differ from a regular woohoo moodlet (in terms of buffs) anyway.
The only difference for a teen that never messes around and becomes a young adult is that they get the purple notification in the notification center that says "x is having their very first woohoo!" when they have their first woohoo as a young adult.
I'm ok with not seeing that notification for teens that have a romantic history.
