I read a lot of notes saying this runs small so I knit the 12-18 months for my tiny sized 11 month old on size 5 needles (one size bigger than what the pattern called for). I finished it today and tried it on him - it is super SNUG :( I am hoping I can aggressively block it to fit him at least a month. Oh, I also added 10 extra rows in the sleeves after the last decrease/increase and knit the garter ridge section a bit longer, too. Otherwise the sleeves would have been too short.

UPDATE- Even after the aggressive blocking it is really snug. Fit him for maybe a week :(

On a better note - the yarn is such a dream!! I loved knitting with it. I had maybe about 60” of yarn left when I cast off.