I want a guinea pig but i can't convince my mom. HELP!?

I have done everything! I have done all my research i know everything a person could know about guinea pigs! I have researched other animals and this one matches my life and me the best. I have put together a powerpoint with pros's con's and dietary needs. About how they need a friend. C&C cages. Costs. How i plan on paying. I even put in fun facts and pictures! I haven't had a meltdown. I have stayed calm and nice the whole time! Earlier today i brought it up. And she asked me alot of questions and i could answer them by heart which impressed her. I had money saving ideas and everything. But im 13 and she thinks im going to forget about the guinea pigs as i get older but im not! A guinea pig is my dream pet! <3 She brought up traveling and diseases. Health. And needing two of everything. And i had answers for everything! I showed her some cute guinea pig videos from youtube. And i checked with her about how she was feeling. And i told her i respected her opinion and that i appreciated her taking the time to listen to me and everything! And i told her im not asking her to rush into a decision. I understand she needs to sell it to my dad and so do i. Im also prepared to wait until Christmas if that's what it takes! Help me please! Any ideas will help a ton! Thanks everyone!