11-year-old with a yeast infection ?
Yes, 11 year olds and even very young children can get yeast infections. Antibiotics are one of the number one causes of yeast infection in children antibiotics are made from fungi and can kill the good bacteria that kids need to stay healthy.
Yeast infections should be looked evaluated by a dr. However, antibiotics are often prescribed and can sometimes exaccerbate the problem. Try to treat the underlying Candida as well to prevent future problems.
To avoid yeast infection in children you want to strengthen the immune system and avoid things that would kill the good bacteria in the digestive system (such as lots of anitbiotics). It is always a good idea to supplement their diet with probiotics after taking a round of antibiotics.