No need to have the cat euthanized. 12 years old is young. Make a vet appointment to check on a medical issue the cat may have such as a uti. Sad to think that your cat has probably never seen a vet.
You may have to bring her to the MSPCA if you don't have a vet. They may be less expensive than the vet. I feel for you, as we had to put our 12 year old cat down 3 weeks ago when she stopped eating and the vet found a cancerous tumor in her mouth. It was really sudden and we were devastated. It was costly, but we ended up adopting a five year old cat from the MSPCA in Brockton. They understood what we went through, and were very helpful.
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