For my tiny daughter, 12 years old:

I CO 32 sts to knit the ribs 2X2 instead of the 30 in the pattern. 22 rows. On the last row of ribs, I dec 2 sts to arrive to 30 sts and start the pattern.

The mitts are a little bit close for her, but it will fit. If I have to knit another kit, I will knit the adult size instead of the child size. It’s not always easy to know when your teenager become to wear an adult size!

Finally, they are too small. I will knit a adult size for my daughter and find somebody to give the others.