A 10-year-old takes about 11" at second base or shortstop (10.5–11.25"), 11" at third and 11.75" in the outfield. At 10 a player can be in Majors (46 ft pitching, 60 ft bases). Typical hand: 6.5–7"; median height 4'8".
Two charts at 10
Rawlings lists youth 7–12, infield at 10.25–11.5"; Baseball Monkey’s baseball, ages 8–10 band gives 10.5–11.25". They overlap at 10.5–11.25", and the sizer picks the middle: 11".
At 10 a pitcher’s glove (11") wants a closed or basket web, a middle infield (2b / ss) glove of 11" an I-Web, and a third baseman’s 11" an H-web.
The game at 10
In Little League a 10-year-old plays in Minor League (ages 5–12, 46 ft pitching, 60 ft bases); Little League (Majors) (ages 9–12, 46 ft pitching, 60 ft bases). Pitchers are limited to 75 pitches a day at this league age. The next step is Intermediate 50/70 from 11.
CDC growth charts put the median 10½-year-old boy at 141.3 cm (4'8") and girl at 141 cm (4'8"); the 5th to 95th percentile for boys runs 4'3" to 5'0". A tall player at the age is often a size ahead in the hand too.
Check the hand
Rawlings’ batting-glove chart puts hands at 10 in Youth Large (6.5–6.75") and Youth XL (6.75–7"), measured from the base of the palm to the tip of the middle finger. Measure it 1:1 in Mode 01 (finger plus palm): a longer hand moves the pick toward 11.25", a shorter one toward 10.5".
For comparison, the 9-year-old sheet starts from 10.75".