I'm 41. I learned of acceptance at 24. It's hard to answer your second question because it's still a work in progress, and I continue to learn things about myself. However, with other chaos going on with my life, I think about my stutter very little these days. I'd say it was about 7-10 years for me to have a truly different attitude towards my stuttering. It's also very subjective. Everyone has a different definition of acceptance.