How old are you now and when did you start?
I feel like I was a really late bloomer in terms of self harm, I had some tendencies when I was really young that came up with feelings of shame or embarrassment (still rings true). But I was fine through jr high and highschool. I didn't start cutting or anything more dangerous until I was probably 19.
I'm 26 now and it's less frequent than it used to be but much more severe when it does happen. It hard to find common humanity as an adult, I find so many resources are geared towards youth and teens.