Running Limerick

Today's Daily Challenge was to write a limerick. I suck at poetry, so this took forever because I kept getting the rhythm wrong, but then laughed out loud when the last line finally clicked into place. It makes no sense, but that's the point, right? ;)

There once was a girl who would run
always having far too much fun.
She wore a short skirt,
and she liked to flirt.
It's clear that she wasn't a nun.