I started in Grade 5, playing trumpet. By the time I got to High School, I was playing in the school orchestra, a marching band, and a drum'n'bugle corps.
I had a lot of trouble with chapped lips. Its a drag trying to play when your lip splits. So I took up guitar. At the time. (late '60s) , everyone was playing.
Like the song says, "I got the music in me". That's not a boast, even a mediochre musician has a need to play.
Its who we are.