If ya feed the kitty, it's your kitty. S/he'll keep coming back. Check and see if it belongs to anyone (if there are fliers posted, check the newspaper, etc.) If not, check w/the local pet rescue organizations. Don't bring it in the house, especially if you have other cats, until you have it checked for contagious diseases. Maybe Mom will let you keep it in the garage until it's seen by a vet. I can't resist feeding an animal; I just can't do it. But just remember that, if you do, you've got yourself a cat, kiddo.

Good luck and blessings,
M