Complex sentence: As a young teenager he ran away to Boston and assimilated into the literary scene of the city; by age eighteen he'd moved to New York City and where he was accepted as a protege by Andy Warhol.
Split into simpler sentences: As a young teenager he ran away to Boston and assimilated into the literary scene of the city. By age eighteen he'd moved to New York City and where he was accepted as a protege by Andy Warhol.