If you want an easy pet, get a snake, it only needs to be fed like, once a month. And i personally think fish are a waste of space, all my Beta fish Bob ever did was hide under some plastic vegetation for all his 2 years, then it was flushin' time.
You could get a hamster, they're cute and cuddly. Unless you do hamster bowling like my dad did with ours and then it becomes a demon hamster.
You could get a leopard gecko, or a bearded dragon, they're kinda cute.
My number one pick would be a dog, but it seems like you couldn't go for that if the parents say no to a bird. Which you should tell your mom how retarded she is if she's afraid your cockateil is gonna get the bird flu and get all of you sick. That is more chickens and turkeys and birds like that. But i must warn you, birds squak constantly and its extremely annoying, and make sure to spend a lot of time with it because i kinda didnt spend quality time with mine as much as i should and he became an asshole.