“After being mentored by Benjamin Graham, his first investment firm as a professional was Buffett Partnership, Ltd that he created in 1956 at 26 years old. In 1961, after his partnership was worth millions, Buffett made his first $1 million investment in a windmill manufacturing company.”

Not pulled from this, but here is a nice timeline I just found https://www.cnbc.com/amp/2020/08/30/how-warren-buffett-made-billions-became-oracle-of-omaha.html