anneey I agree with OP that if your little friend is eating and seems to be quite happy, then I wouldn't think there is any need for you to rush to the vets just now, as you say you will know when the time is nearer so enjoy for a while longer, we have 2 cats that came from rescue place when they were kittens they are coming up to 13 yrs old and both have started developing bits of things, but one of them Rosie who is so affectionate has a something on her mouth,I have taken her to the vets a few months ago and had an anti biotic injection (£60) I for one cannot afford vets fees now due to my circumstances changing, but I will be taking her up for another consultation most likely next week, she is quite happy and stuffing her face as normal, so we will just have to see what the vet advises which we already know.... biopsies/xrays/overnight stay etc etc.But I will at least get a professional opinion and go from there. I have a feeling it is a cancerous growth.