aibu to be mad at daughters school?

[Mumaof2girls]

so my six year old came home from school yesterday afternoon with a letter about "bring a parent to school day" which i think is quite nice except it's for today the day after reciveing the letter...now I work and can't just randomly take the day off with such short notice now I'm at work currently feeling guilty and worrying about how me not turning up will affect her as most of her friends mum's/dad's may attend also.
aibu to be mad at the school for not giving enough notice?
I did speak to her and explained mummy has to work so I won't be able to make it and promised that the next trip that comes up (as we usually get longer notice for trips) I will go on with her. she was pretty happy with this. but just can't help feeling guilty and sad that she will be disappointed that I'm not there. am I just over reacting? ☹
Thanks.

I would check the date on the letter, but if it is recent, I would ask the school why they didn't give more notice so that working parents could make arrangements if they wanted to.

Our school used to have form for doing things like this, but they now send out group text reminders and group emails, so it is a lot better.

That's very difficult. Does the school have a website, or a calendar you can sign up to? I find that helps

thank you all for your replys. I will pop into the office when I drop her off in the morning and ask politely if they could in future give more notice. spoken to friend who has picked her up from school. she is completely not fussed about me not being there today. just me over reacting 😂 she is completely fine.