How old was Kurt Cobain when they released 'Nevermind' with Nirvana?

Kurt Donald Cobain was an American musician and songwriter. He was the lead vocalist, guitarist, primary songwriter, and a founding member of the grunge band Nirvana. Through his angsty songwriting and anti-establishment persona, he widened the thematic conventions of mainstream rock music. He was heralded as a spokesman of Generation X, and is widely recognized as one of the most influential musicians in the history of rock music.