Great Balls of Fire! (1989) on Netflix

Sneaking with cousin Jimmy Lee to check out the dancing people at the Chocolate Bar, Jerry Lee, for the first time hears the piano, playing in a style he soon learns to play. Now living with his cousin J.W., he meets 13 year old Myra and they soon fall for each other. Now Jerry Lee is a rock star and decides to marry his cousin, which started his down fall. The question is will he make it, or will his young wife and his stubborn pride keep him from being the killer himself?