If your business has a legitimate reason for not being able to provide services to children under the age of 10 years then there is no discrimination based upon age. In fact, many retirement communities have age settings for people of 55 years of age or more to be residents and those have been held to not be in violation of the law.With respect to your spa and saloon, I see nothing wrong concerning a refusal to provide services to people under the age of 10 years from what you have written.