I was 40 years old before I became an overnight success, and I'd been publishing for 20 years.

It takes 20 years to make an overnight success.

Actually, I'm an overnight success, but it took twenty years.

I'm what is known as a 40-year overnight success.

Things that look like an 'overnight success' typically are not.

My overnight success was really 15 years in the making. I'd been writing songs since I was 6 and playing in bands and performing since I was 14.