How to convince my parents to get me a guinea pig?

okay i did alot of research on bunnys and guinea pigs. i noe about almost everything about them! once on my birthday this year i went to the peninsula humane society and was about to get a bunny! (with my own money too! ) but my parents disapproveD! my mom ,before, used to raise animals like rabbit to eat them. I mean that wouldnt be gross back then but now ofcourse! she said i cant get a small pet jus tto play with. she said dey were gonna stink up the house and expensive! fleece for bedding is great right? money saving & also she said i would hav to let it live in my outdoor shed... i dont tink its safe because of the conditions YAAY HELP ME D:< my awesome nerd paragraph 8|