Hey there, I'm 21 and still can't get away from
SH.
I don't think you can grow out of it. It's not some bad habit you can just stopp. It's a coping mechanism and can be an addiction as well.
Stopping
sh is more about finding different ways to cope and solving what brought you to it in the first place and that has nothing to do with age. Some problems solve themself while growing up, but some don't and you will always encounter new ones.
Well what I'm trying to get at, people selfharm at any age. Sure, it's more common or known among teenagers, but adulds selfharm as well. Even old people who are 60 or even older can self harm. It doesn't have an age limitation and you can't just grow out of it. It's a learning process that takes time and some people need more, some need less time.
If you ever want to talk with someone about this, feel free to
pm me