bellajane:
I think not getting asked to something does hurt - but you can't force situations.
I get that you're hurt for your daughter (and I've been there too - either because DDs were not invited or worse yet we had other plans so they couldn't go - the latter actually makes me feel worse to be honest).
I think you just have to relax about this but I do get that can be really hard.
I think all you can do is realise that sometimes friendships also involve wider circles.
As you may have surmised I'm a rather bristly personality and doggedly independent - so that's off putting to certain Mum's. I'm also not very 'girly' - an academic pushing 50 doesn't help either. I'm genuinely friends with several mums now, but it has taken nearly 7 years to get there.
Some of the mistakes were mine. DDs are invited for play dates and when I drop them off I'm asked to come in, only I have to dash off to work, drop other DD somewhere else, etc... I didn't mean to cause offence and felt awful in one case when the Mum had prepared lunch, but I genuinely didn't know that was going to happen and had an important meeting at work 15 minutes later so had to go.
I think the way to look at it is you can't always win. Be glad that your daughter is well liked and plays well with the other children in school.
The good news is from senior school it will be more about who the kids want to be with and less about what you or their parents want.
Remember there's always 2 sides to every story - and it may be that genuinely the child's parents could only ask X many from school, because cousins, friends outside school, children of family friends were also coming.
My advice is the day of the party (if a weekend/ evening) do something special with your DD - go see a film, go to the park, fly kites, etc... It won't totally make up for it, but it may help her not feel as left out.
HTH
HTH