Children are usually placed in age groups based on their birth date. For most leagues, the way to determine a child's "soccer age" is to ask "How old was the child on last July 31?" For example, if a child was nine as of 7/31/10, they will stay in the "Under-10" (U-10) group until 7/31/11, when they move up to U-11. This is how it is done at all the soccer programs I know of, but you should check with your league if you are unsure how they determine "soccer age". You should keep in mind that a child with a July birthday is almost a year younger than a child with an August birthday (even though they may be the same "soccer age") & that the younger children often have shorter attention spans and often won't learn as quickly as the older children.