I made a few small changes to Ria’s pattern:

1. I used a J-hook for the starting chain to make a stretchier arm-hole, then switched to an H-hook for the rest.
2. For round 18, after stitch 22 I chained 1 and then joined. Then for round 19 I put dc’s all around including in the join for a total of 24. That was the only way I could figure out how to get 24 dc’s without getting extra bulk at the join.
3. I added a thumb by single crocheting around the thumb-hole (15) 3 rnds, then for the 4th rnd I did 5 sc, 5 dc, 3 sc, 2 ss to create the outer bend in the thumb.

I also created a hat pattern to match, my project “Kyla’s hat” (last photo).