Rabbit? Hamster?

Yesterday, mum told me that one of her friends want somebody to adopt a rabbit. I like rabbits and i want it for sure. but the problem is ...where can I put it? Will I have enough time to take care of it? Will dad agree with it?(Mum'll agree it for sure) Mum said that the rabbit is just like a puppy. it likes to walk around and the speciallest thing is that it can poop or wee in her own cage! well, so it's not really a great problem getting her, right? but are you sure that dad won't disagree? What should I do? there's not always a chance to adopt someone's healthy rabbit. Should I use my brain and think of ways? or should I just ignore it and continue on my school work? I want to take care of it. but those problems are..making me hesitate.....