It was exactly what I had in mind - younger cats get adopted more often, and people are afraid to give senior cats a chance. So I was like "imma be a bigger person and give an old cat a home".

I researched local shelters and went through multiple pictures of cats. The oldest I found was 11 years old and had already spent 2 years in that shelter. I was like "yea thats it, this cat will die in my loving home".

The shelter gives you the address only if you decide on coming and picking the cat (nesessary because people will leave their unwanted cats at shelter's doorsteps if they know the address). I called them, said I wanted the cat, went to pick her. 10pm, complete darkness, the shelter is in -1 floor in the middle of an abandoned factory. I thought I'd end up in the missing persons list, but no. They gave me the cat, sorted few documents, even let me use their cat carrier so I could safely transport her home. The cat was growling every time someone got closer to her, like this quiet very low "RRRRRRR" sound.

Picked her up, left the factory, somehow found my way back to the light where I could call the taxi and go home. At this point the cat stopped growling and switched to opera. I had no idea how 3.5kg cat could produce a sound this loud.

Got home, let her out, she immediately found her way under the sofa. I was satisfied - got an older cat, didn't die myself. Preparead a bowl with dry food, water, and toilet.

Next four months I basically didn't have a cat. Cat poop would respawn in the toilet, cat food and water would disappear. I kinda accepted having a ghost cat at this point. Then she started to leave her hideout about once a day when I cooked. She'd sit behind me, as close to the sofa as possible so she could see me, and watch me cooking. If I turned around, she'd hide back.

5 month: she explored a chair. Never relaxed, she would just sit on it, angrily watching me and rushing back under the sofa if I moved.

8 month: stopped running when I moved.

1 year: she let me pet her. I sat on the floor and slowly moved to the chair, and she didnt run away. When I moved my hand towards her, she got very tense, but then started to literally bash her head into my hand and scream. I went like "if she dies tomorrow, my goal is fulfilled, a senior cat got comfortable at my home".

2 year: she's still hiding when someone moves, but sometimes allows me to pet her. When pet, screams and pushes her head agains my hand.

3 year: developed an allergy, I started regular vet visits and checkups, changed a bunch of cat food from made of almost 100% meat of different kinds to medical cat food. We tried like 20 different options, sometimes with medication, somethies food alone. Cat dying because it has allergy and scratches itself to death wasn't my idea of "dying peacefully".

4 year: found good medication that helped. I was like "yes, now it will be peacefully".

5 year: all her gums got covered in open wounds in like a week. I was terrified. She stopped eating, peeing, pooping. I noticed gums and rushed her to the vet. They ran tests, which showed "Feline immunodeficiency virus", which sheleter hadn't warned me about. Vet gave me one option - to remove all her teeth, with very high chance of the cat dying during the procedure or shortly after. I thought if she dies, she migh as well die a warrior. Agreed to the surgery. Surgery took about an hour, but the cat didn't wake up. She was alive, sleeping. I brought her home. She stayed in the same condition for the next day as well. I thought at least she's sleeping and not feeling pain, if that's the end - not the worst one. 2 days after she woke up, drank water, peed over all bathroom floor and continued to act normal.

6 year: she started to react at toys. All the time I'd been having her, I tried to play with her to see if she's interested. And now she suddenly was interested, she'd roll on her back and smash the toy with her paws. She also tracked the toy with like half of her body. She had horrible delay - maybe half a second before the toy passes her and her finally moving her head to where she thinks the toy currently is. I also finally found cat food that didn't trigger her allergy and allowed to stop medication.

7 year: she started using 2-meter tall cat tree, she just runs up the tree and down. Vertically.

I don't know where my plan about giving this cat a peaceful end of life failed, but I'm happy it did.