how to stop friends from seeing facebook posts and stuff?

[jamie]

Ok, so my mom won't let me have a facebook unless she is my friend, and I wish she just couldn't see anything I post without figuring out that I blocked her or something. just a few minutes ago I commented jokingly on a friend's wall about how the test we have to take is hard and we will all probably fail it, and within seconds my mom was in my room screaming at me to study for it and slamming the doors. I just wish she couldn't see anything I post, because it is ruining my LIFE. AHH, so if any of you know any handy little tricks, I would greatly appreciate it