a young child
Children between the ages of nine and 11 typically wear a size youth large. However, it is really based on the size and not the age. Children that weigh around 100 pounds can wear a youth large.
age 10-12
no..it will only fit a youth size helmet
You would most likely need a Youth XL...chest size 38-40cm
It depends how tall you are but its probably around 16-20
Well, it depends many youth mediums are different so try it on first...
Not all 11 year-olds are the same size. You'd have better luck getting an accurate answer to this question if you gave an actual youth size to compare to.
10 (Someone has stated the answer is a size 10) However, I wear a 35 in European shoes and a 5-5.5 in women's USA sized shoes. Rarely, I can get by with a small sized six. In youth I fit a size 4 quite nicely across the board. The youth sizes fit better most especially if you have thinner legs and are struggling with boots that are too large in the calf. Good luck. I suggest a size 4 youth in boys/girls.
I'm 20 and I fit size junior small but I have since I've been in middle school
Around 4 years old, sometimes younger
If you were going for the smallest size, I would say that you had to be about 12 to fit Hollister trousers, it also depends on how long your legs are and how wide you are.