WWYD - dance show or cousin's birthday party

[HanaPales]

I know this is quite a trivial problem compared to many that are on MN but it has me and DH scratching our heads a bit as to the right thing to do.

TLDR; My DD has a dance show and her cousin's birthday party at the same time. Which one would you choose?

For more context:

My DD is 4. She started ballet classes in September and really loves them. For the last few months she has been showing us at home a special dance they've been learning. We've just found out that this is for an end of year show, at the end of this month. It's in a very fancy theatre in the city centre, and is a big deal for the dance school.
The problem - it is at exactly the same time as her cousin's birthday party, which has been planned for a couple of months. We are close to my BIL and his family, and my DD adores her cousin. Also, my DH and I had offered to help run an activity at the party (nothing complicated, think egg hunt or quiz or similar).

What should we do?! I know that she's very little so it's not like she'll do a fantastic performance or anything at the show, but she will be pretty devastated if she can't do the dance that she's been practicing (also, when we mentioned to the teacher there was an issue with the date she looked very worried and said she really needed my DD because she was the strongest dancer in her group and the others would copy her). I admit that I would really love to see her do the dance on stage!

On the other hand, I'm pretty pissed off with the dance school that they've only told us with such short notice about the show. Family is important to us and we will feel very guilty about missing the party. There is a chance we could rush off after the show and arrive towards the end of the party, but it will all be a bit stressful.

So WWYD?

My DDs school just charged a fiver for each costume required to cover dry cleaning and replacement of older costumes. To be fair each set of costumes was used for years!
If a parent was willing to go through the process to get a chaperone license to supervise backstage, we didn't have to pay for costumes.

Dance show, then try to get to the end of the party, your DD can have some time with the cousin and some cake and you can offer to help clean up which I am sure will be as grateful received as the help at the party. Tiring day for you, but typical situation unfortunately and I’m sure there will be many more like it.

I vote for the dance show.

They agreed to help with activities at the party so clearly have already agreed to go

As its a family party I'd go with party. My answer would differ if it was a friends party.

Alternatively can you arrange a bday day out/activity with the cousin on another date?

Our school isn’t that bad but I was also clueless about how the costs build up! We don’t pay for extra classes or for the rehearsals though, so that’s something 😂 But the costumes, the make up, the hair stuff, all the little extras, oof. It’s been 3 shows for us last few years but it will be 4 this year, we usually go as a family to the first one and then alternate going just me/DH for the others because it’s ridiculous spending that much money x4 but I also don’t want my DD being upset that no one is watching her dance and obviously they benefit from us sentimental parents 🫣

Do the show then take your niece out for a special day out with her cousin at a later date

I'd personally choose the dance show.

However, it's very poor of her dance school to only be arranging this now. My dd had her dance show last weekend and we knew the date in January!!

Party

100% the dance show missing something your daughter has worked hard on and enjoyed takes place over anything else.

Dd3's dance school is the same - a show every 2 years and we were told the dates a year in advance! She is intermediate standard now so they'd probably miss her if she wasn't there and she helps the little ones with their dances. It's a lot of fun for young ones and she'd definitely feel left out if she didn't participate. Our school normally have the young ones on first so you might be able to leave after her dance and still get to the party.

Thanks again for all the input here! Just to update: we decided she would do the show. She spent all day at the theatre in rehearsals and had the time of her life. When the show came she did her little bit on stage very nicely (proud mummy and daddy with a tear in their eyes), then the teacher rushed her straight to the stage door so we could whisk her off to the party. Arrived just as the last guest was leaving 😥but the family were still there so my DD still got to play with her cousin for an hour or so. She was absolutely exhausted by the end of the day!
I'm glad we did the show because my DD has said multiple times how much she enjoyed it, although I do feel a bit guilty about my niece's party.
Just hoping we can get some info from the dance school more in advance next time, although from talking to some of the more experienced parents it seems the organisation is always like this 😖