Most of us are adults past puberty who are still suffering from acne.
You're right - for lots of people, acne is a normal adolescent experience that they "grow out of," but some people continue to break out for years afterward.
When a person has had acne for 10, 15 or 20 years, it takes a serious toll on their feelings about themselves and they start to get pretty desperate. It's not fun to deal with this every single day, year after year.
Hopefully, you will not have this problem and will leave your acne behind when you're done with puberty