Thinking this will just become a boy/girl split

[Caitily]

My DD is 4, about to start at an independent prep school.
We received an email a couple of weeks ago about the introduction of Karate and Ballet into the curriculum in response to calls from parents for more sports. It is a small school, one form entry no more than 22 pupils per class, so really looking around the 150 total. They have an AstroTurf playing field on site, but its small, so once a week all kids travel to the school playing ground, it is about 15/20 minutes walk away. They also go swimming once a week, offsite.
In the email they asked that parents/pupils pick either Karate or Ballet for the school year, they won't be able to swap back and forth and will be encouraged to continue with the same sport all through school. DD wanted to do ballet, we watched some videos of karate online, my DH showed her some bits (he used to do taekwondo, so picked similarities), she still wanted to do ballet (she does it out of school too). Everyone girl parent I've spoke to so far has said their daughter has chosen ballet, all the boy parents say they have chosen karate.
We chose the school as it is co-ed, and very quickly I can see this turning into girls do ballet, boys do karate. Even if a girl wanted to do karate or a boy ballet, I can see there being peer pressure to pick the other and not be the only boy doing ballet etc.
AIBU to think this is going to happen and its a terrible idea?

How's that the same? It's telling people they can't do something they want and have to do something someone else thinks they should.

I agree with you. I think they should both have the opportunity to do both.
It's pretty sad tbh that they're already socialised so strongly but that is the society we live in.

At that age both ballet and karate are surprisingly similar, both require balance, poise leg strength, and a certain amount of mindfulness. I mean in an ideal world you'd do one for a term, one the following year and pogo sticks in the summer term, but both ballet and karate build excellent skills. You can always find a class outside the school day in either disciplines, so I don't see a major problem here.

Following term dunno why I typed year there!

So your daughter is getting the choice to do ballet or karate and that's sexist!? How? Your 4 year old daughter has chosen ballet of her own free will and that is sexist!? How? She already does ballet outside of school but that's not sexist I presume?
You say your 4 year old hasn't yet started at the school. So how has she been pressured into doing ballet by the other kids? Has she even meet them yet?
Girls on average prefer ballet to karate. Do you think ballet is a lesser sport to Karate? Because if you don't why is it a problem? I'd understand if you tried to encourage her to do karate for variety because she already does ballet outside of school. But it seems you think karate is the better sport for your daughter because boys are more inclined to pick it.

I would sign my child up to the one they wanted, I don't care what other people say unless you are forced not to chose then the pressure is self inflicted