Am I right to be pissed off or am I over reacting

My ex mil looked after my daughter yesterday while I was in work. She has always overstepped the mark with everything, that's just the way she is. She always has to know the ins and outs of everything and has to be involved with everything. That's her personality, but because she's my daughters grandmother obviously I want them to have a relationship. So yesterday while she was looking after her she was messaging me throughout the day keeping me up to date with how my daughter is doing etc. It is also my ex's weekend to have her so it was arranged that he would pick her up after work and she'd go to his, meaning I wouldn't see her from Friday morning until Sunday afternoon. Anyway, late last night I get a message from my ex mil informing me that she had cut my daughters hair!!! My daughter has long beautiful curly hair and she cut it! Her exact words were "I cut her hair, I cut loads off but it's still long, I just thought it needed cutting, hope this is OK". I'm so pissed off, I haven't answered her message because I don't want to cause a fuss but I'm so angry! For a number of reasons (1) it's not her place to 'decide she needs it'. (2) fucking ask one o her parents first! (3) it's not your place to decide when and how much gets cut off! (4) you've been messaging me all day but chose until late last night to tell me, therefore you had plenty of time to ASK!!

I won't see my daughter until tomorrow when she comes back from her father's so I wont even know what it looks like until then. I personally think she's overstepped the mark and while I'm grateful for the help in looking after her while I was in work, cutting her fucking hair was NOT part of the childcare! The one time I ask her to help and she does this. It's safe to say she's not having her again, she'll be in proper childcare from Monday!