Is this a good plan for sneaking out tomorrow night?

There is no amount of good grades and good behavior that you can display to make it "okay" to lie to your mother or sneak out to a party. Your mother is protective for a reason, you are still a kid. Even if you don't plan to drink or do drugs, there may be many other people there who are doing those things. People under the influence of drugs and alcohol could hurt you or rape you.