at this age your child should get at least 10 to 12 hours of sleep. this is a time of growth and overall development for your child, and sleep time acts as the perfect time for your child's body to rest, as well as grow the way it should.
here are a few links you may find helpful, that talk about the ideal sleep time for kids around 6 years of age
https://sleepfoundation.org/sleep-topics/children-and-sleep/page/0/2
http://www.webmd.com/parenting/guide/sleep-children#1