GRE is not related to law school in any way, you just need to take the LSAT. Shoot for the highest gpa you can possibly get. The age you are when you graduate will have no affect in your admission...
Don't knock it until you've tried it bro. What is there not to like? You save time (don't have to sit down on the toilet), you save money (you're using the water in the shower anyway), and it's...