If she asks to do something all you have to do is say "thanks for the invite but I have a lot going on and can't go". Just act busy, better yet, BE busy. It can be anything. For instance, you could be studying for something. Like, a certification of some kind. Takes up a lot of your free time and can't be monitored.
Me:49 W:45 M:19 T:22 EA confirmed and ended 8/2014 S:19,17 D:9,5