as someone who tried to "fix" it in their childhood by going to many doctors and speech therapists, you did not miss out on anything. there is no "fix" even if you went to therapy as early as 5 years old. it is very common for children to get rid of stuttering when they grow up and it goes away by itself, not with therapy. my childhood friend who stuttered when he was a child never went to therapy and it went away by itself as he got older and now he doesn't stutter at all it is all luck whether you get rid or live with this curse for the rest of your life