if she is peeing on the carpet it could mean she has a bladder infection or crystals in the kidneys, you need a vet to diagnose and treat this condition, if it is the other it could be just old age at 16 she looks to be doing really well, when they get older they often lose weight and it is often the kidneys or teeth playing up, she is well padded so she looks to be in good health,
if you feed her lots of cat biscuits that can cause problems so as a cat breeder for 16 years my best advice to you is to take her to the vet for a thorough check up, it could be just a case of her getting incontinent with old age, let me know how she goes