Styxie
I Love YTtalk
Contracts aren't legally binding if you are under 18, so he wouldn't technically be in a contract.I would seriously advise against this. Fraud is no joke when it comes to these things. You're entering into a legal contract.
Just show your mum your channel, and say that you can earn revenue from it. But if she says no you may have to just accept it. You can't 'make' her do anything, she's your parent!