Friday Night Funkin' is a rhythm game that contains mild cartoon violence and suggestive themes. It is rated for teens and above, so it may not be suitable for all 13-year-olds.
Some of the roasts have swears. 2 of them replace F-word with funking. In week 7, at the 3rd cutscene, Tankman calls boyfriend/girlfriend a "c*nt" 2 times.