I think thats great that you pay her what you think she is worth insted of some of those maid cleaning services that charge X dollars per hour and give them 8 bucks an hour no benefits.
Cleaning houses is hard work, and tho anyone can do it, it is still hard work worth good $$ if you find a good cleaning lady who actually disinfects instead of just wiping stuff down with a dirty lukewarm rag to make everything look "neat".