I’m making this sweater for my 8mo son Oleg.

I took the largest size of the free pattern and enlarged it to fit my kid.
Separated body and sleeves on row 38, when I had 132 sts for body and 40 sts for each sleeve.
Backward loop CO 2 sts for underarm, picked up 2 sts from them when started sleeves with magic loop method.
Narrowed sleeves, started decreasing from row 14, k2tog at the beginning of the row, ssk at the end. Repaeated these each 3 rounds for 9 times.

Ran out of the main color yarn, so I had to make the collar in white and to do some experiments with the stripes on sleeves. I really like how it turned out.

The finished sweater will rather fit a 3-year-old kid, then my 10-month-old, but hey, he grows so fast!)