Jesus, that's a huge violation of privacy. I'd be furious. You've every right to your own space, no matter how old you are, or... anything, really. I'm sorry, OP. I don't know your mom, but I'd make it clear how hurt you are and how much she violated your trust, and regardless of whether she's the kind of person to respond to that or not, hide the diary in future.

Dear Diary, Today Mum read through you and invaded my privacy. I feel hurt and betrayed but my Mum is still the best Mum in the world and I hope she raises my allowance to compensate.

That's terrible. I feel for you.

How disrespectful of your mom to do that! Best to find a better hiding place for it now :( The fact that she wanted to make it so obvious that she's read your diary is just, wow... I've been writing diary entries since fifth grade and have always kept them in a box that's got a lock on it. No one knows where I keep the key, mwahahahaha (or so I think O_O)...

Hey look, another thing to put in your diary.

lol, my mum did this to me when i was younger, though she didn't read it properly otherwise she wouldn't have been so suprised when I came out of the closet ?

Depending on what words were misspelled and how many this could be a FML for both mother and child.

and you correct the mistake of her being alive?

put a look on ur diary and hide it.

learn to spell then, jesus.