Complex sentence: But after two years of begging his parents, at age 14, they allowed him to practice Tae Kwon Do, he picked it up very quickly and after a few months he got in a street fight with the biggest bully in town.
Split into simpler sentences: But after two years of begging his parents, at age 14, they allowed him to practice Tae Kwon Do. He picked it up very quickly and after a few months he got in a street fight with the biggest bully in town.