I'm getting excited

I have my gender scan today in a couple of hours. But I made the decision that I'm not telling people what the baby is. But I think it's totally unfair that they told me they will ask my 2 kids what the baby is as I am telling my kids as my son is freaking out as he doesn't want a sister and I was advised by his school to tell him so he can get used to the idea.

Plus its confusing for my youngest as I'm telling him not to tell anyone and they he hears people saying 'it's ok I will ask the kids