My mum always tells me what i can and can't do and its driving me up the wall. She say's that i can do something tomorrow and then the next day, she say's i can't do it and she says i can do it tomorrow instead but then she won't let me. ect. etc. is it normal?

in the point of my view this kind of problem released by mothers !
it sends the wrong impression when first she says yes, then no, then yes.
no wonder you find it annoying.
Personally though, I have to say that is quite annoying.