Well, if it's your dream and what you really want to do, I wouldn't let her stop you. If she loves you she's supposed to be supportive, and it's not like you're telling her you want to be a sherpa in the Himalayas. You're wanting to be an attorney and hopefully work your way to being a politician, which is hard, but is definitely doable. She doesn't really have a right to try and deny you that.