What to do about a planned toddler’s pool party birthday?

I’m currently one day short of 36 weeks and would be 39w4d by the party date if I haven’t given birth already. My first kid came at 37 weeks so idk if that’s any indicator.

The event is a friend’s toddler’s 3rd birthday celebration - super fun pool party in a water park. I would absolutely want him to go! We already had to skip his own 3rd birthday last week because he got sick and we also missed this friend’s 2nd bday because of illness and this would be an amazing experience for him. We would not be able to substitute anything similar anytime soon.

My issues are - god, I don’t see myself being comfortable at almost 40 weeks rolling around the kiddie pool. Idk if the facilities are suitable for a stranded whale. I also do not have anything to wear and after trying two weeks ago, I learned that it’s very hard to find anything that I’d be ok wearing and can fit into and also afford. Otherwise atm I do not feel particularly uncomfortable this pregnancy, except my size.

The timing and risk to catch some illness. Neither a sick me, toddler or newborn is something I want to experience at this time.

If my husband goes with our son and I stay home, I’m sort of left without any support and a car. My only option is to call an ambulance in case I go into labour and deal with it all alone. I’m not from US tho so it’s not a cost issue, just somewhat not what I’d want and would stress about. And if baby is already born I’d assume husband would be tired too. And the illness risk again.

So I’m here asking for opinions and maybe some suggestions I haven’t thought of. And maybe I’m overthinking it all? Has anyone had any similar experiences/decisions?