Third wheel?

[ChocolateRebellion]

Three middle aged couples, friends from university are going out for a meal next month. Out of the blue one of the group asks if her DC, late 20's can join us.

We have nothing against DC, but we don't see each other very much and think this will change the dynamic.
Nobody wants to say anything, AIBU to feel pissed off by this request?

I'd be pissed off too. It completely changes the dynamic.

Bit odd, why would the DC even want to come? I’d probably respond and say ‘I’m surprised DC wants to come and sit with us old farts haha!’ or something lighthearted like that which still expresses your surprise.