Gauge is not critical.
You can make it as long as you like.

From the description:

If you’re looking for a great first project for teaching a child to knit (or an adult, for that matter), this simple skinny scarf is a great way to go.

Knit with an easy working wool yarn on decent sized needles, it will knit up quick even for a new knitter and can be used as a scarf or belt and made to whatever length you like.

It provides lots of practice on the knit stitch and a little extra fun with the tassels.

Originally published on About.com, currently found on The Spruce. (I am no longer affiliated with the company so I cannot edit pages there. They redirect and delete pages a lot so you may want to download/print to save.)