To not let my children go away without us for three days?

[happypaints]

My mil wants to take my sons for three nights so they can take them somewhere.
Over dinner I was asked to ‘send some dates that they are free for X trip, they’ll need three nights’.
All said in front of my children and without prior discussion with us.
I haven’t sent dates yet, I actually don’t want to at all! My youngest isn’t nearly old enough for this sort of trip, we haven’t done this sort of trip with them yet so I don’t want to miss out on their first, and I think three nights is too long.
AIBU to not allow this?

But they are for 8 year olds. And it's ONE night difference even if it was 2 nights ( the op said 3 nights away)

My DDs brownie camps were 5 nights. They went at 8 years old

I took my 7 year old grandaughter away for three days abroad and she loved the adventure. Remember they have actually brought up children themselves. I dont get the “ we wanted to do it first”. The children wont care and why would you stop them having a great time.