I would have said the opposite, lol! That a 12 year old won't have the energy to keep up with a kitten and will be annoyed. That an adult, even just 3 years old, will be a better fit.

That said, I started with adults, went on to bring in 3 andd 4 month olds, and have had success.

Either way be realistic: you can't make them be best buddies, playing and snuggling up together. You CAN insist they live together in peace and harmony.

When I have my 1st cat and went in to adopt my 2d at the local shelter, they suggested I get the opposite sex. That seemed to work.

What ever you decide, rescue is the way to go. Best wishes! Hey, let us know what you do, and post piccies!