I made a bunch of changes.
Phoebe is a tiny 6.5 year old with a 22” chest. She did not want a belly shirt and prefers some room in her shirts. Since I’m using a linen cotton blend that has varying thickness, I cast on 120 stitches.
Separated at the arms holes with 60 in front, cast off 8, knit 44 on back and cast off another 8.
I decreased to 42 stitches on the front and 24 stitches on the back.
Next time, I would decrease on the front every RS row until I got to 32.

Loved this! Not even a whole skein was used!