Older cats are generally more likely to suffer from dental disease, so don’t panic if you see something unusual but alway get it checked by a vet. If your cat does not tolerate you opening their mouth, you can save this for the next visit to the vet. Some cats will let you open their mouth completely, and others will let you gently lift their gums to expose their teeth - the key is to always be careful, and if your cat seems stressed, ignore checking the mouth for now.
The gums should be nice and pink, similar to your own, however some cats have darker pigments present. If the gums ever look pale, white or yellow you must visit your vet as soon as possible, as this could be an urgent problem.
Cats teeth should be clean and white, with no cracks in their teeth. If you notice any discolouration on the teeth, a dark yellow-brown colour, this could be plaque, they may be due a clean!