I adapted the pattern to make a larger size.
Cast on 76 stitches with a size 6 needle. On row 5 k4, p8 pm, p14 pm,p25 pm,p14 pm, p8 k4. Did increases as stated in pattern but continued for a total of 19 eyelet increases before binding off the sleeves.

Underneath garter stitch band I increased in every 4th stitch (total was around 176, I forgot to get a count).

Omitted the eyelets on the skirt as the stripes made it busy enough.

Total length of the dress (collar to hem): 18.5”
Length of the skirt below the garter band: 10.5”

Finished size is in line with 2T garments. The arm holes are wide enough and the knit stretchy enough that it fit my 5T son as a tunic. It’s definitely designed to be worn long term.