Help! How do I convince my mum to let me have a small dog?

Well, I have 4 cats 1 rabbit and 1 guinea pig. Anyway, i've always wanted a dog to play with. It's so boring round my area. My mum is not a dog person-she thinks they are horrible and mean. We had a dog once but we had to it away. We have a field right up the road from us and I am willing to wake up at 6 Am to feed Her/him. She knows I will take care of him/her but she wouldn't budge. I'm sure the cats won't mind. I just want a small dog who is quiet, Can you help me with convincing her to get a small dog, please!? Also I do my homework My grades are up to scratch please help!!!