I want it, they want me too..?

so i have reasonable parents, but they aren't sure if i am responsible enough for a sugar glider, well i guess they think i can, but how do i talk them into getting me (letting my buy,) a Sugar Glider. ive babysat one, but here are the GOOD things i could mention : i live in the basement, (they live upstairs) ive got a good cage, i can afford it, ive got toys, im responsible with a dog. and also how to i start the convo ? "hey mom and dad i want this NOW!" seems a little bratty and rude.. so could anyone help me here? (: