I tried taming an abandoned cat in my neighborhood; he was a very large adult. One moment he'd be sweet and friendly, the next, a psychopath.; At one point, he ran away from me and did the Trinity wall-run from the beginning of The Matrix (where she kills the cops). Seriously, he jumped up SEVEN FEET.
On the otherhand, I've caught two 4 month year old kittens that are strays, same neighborhood. While a bit skitish, they were basically tame and friendly within 36 hours. Both cats would jump on my bed at night and sleep with me. Their parents, though, weren't really adjusting. I had to let them go as I don't enjoy the smell of cat piss in my apartment.