Finished measurements:
Chest circumference 23”
Back length (shoulder to waist) 8”

From web site:

Hand knitting Pattern for a Toddler size Bolero. The pattern is written for a worsted weight cotton knit to a gauge of 18s x 28r = 4 inches. It could also be knit in a similar weight merino or wool blend for a cool weather vest.

Materials
Yarn: 4 oz. worsted/Dk weight cotton yarn, wool or wool blend can also be used to make a cool weather vest.
Yardage = about 180-200 yards.
Sample was knit from Alpine Cotton – (1) 4 oz. skein (197 yards) Lavender
Also (1) 4 oz. skein Andee 50% Superfine Alpaca 50% Wool (250 yards) Sky Blue

Needles: US #5, #6 and #8 for the cotton (or size needed to achieve gauge)
US #7, #8 and #10 for the wool blend (or size needed to achieve gauge)

Tapestry needle: for seaming
Button or toggle if desired for front (optional)
Crochet Hook to make loop for closure (optional)

Gauge
18s x 24r = 4” in stockinette stitch on middle size needles