AIBU to feel hurt about last minute party cancellations?

Even 50 years ago when I started school it was the same. My birthday is 31st Aug so never really had parties due to it

It's a bank holiday weekend - the last one before Christmas - so people may be going away. I don't think it's a reflection of how much people like your child or you. Is your child disappointed or just you? I suspect she'll still have a lovely time. Maybe have her party in early September next year?

I agree it's probably the time you are doing it. I think a lot of summer borns either go early and do class parties in July or go late and hand out invites first week back for mid September.

As the PP says, in June people aren't likely to know what they will be doing that far ahead and as it's a bank holiday weekend I would suggest many people use that as a long weekend to go away on a mini break or visit family.
Also as some schools are still on holiday and don't go back til the week after, sometimes the last week can be cheaper so some might be odd on a last minute week away.

It's very disheartening, especially when you are the type to make an active effort to attend parties and events.

Unfortunately the timing of this birthday / party probably plays a huge part in dropouts. In June, people have no idea what they are doing a weekend in August. Add to that they won't have seen eachother for a few months. Plus, people end up on holidays or even just doing their own family stuff before back to school.

I know a friend of mine has a daughter with a birthday end of August (a few days ago). She sends the invite home the first week of school, and has a party mid-September. Yes, it's 3 weeks late but she just takes the birthday girl to softplay or somewhere for actual day.