Whole class parties

[Ntsure]

For a 6th birthday party, but in mixed year group classes- who do you invite, the whole class? The class group changes every year
that would mean inviting lots of children ds doesn't know and leaving out lots from his old reception class. Or do you pick 20 or so friends from school (ds doesn't have 20 friends obviously but we'd go with mostly kids from his old reception class I guess)

No idea what the AIBU question is to be able to vote, but

You ask your dc what friends they would like to come, and you invite them.
They know who they play with at that age.

Just invite the children your child wants there