First ultrasound appointment

So my boyfriend and I have our first appointment tomorrow... No other appointments available until I'm almost at 12 weeks and since I had a miscarriage before I don't want to wait that long.

Because of the hurricane the schools have closed and my boyfriend wants to take his kids with us, since we don't like the idea of them being alone during a storm.

I do not want them there for the first appointment.

1) They always manage to misbehave and piss me or their father off..... And has a temper fuse that is super short. This is supposed to be a happy moment and I don't want it messed up. (They're 15 and 9 which is why dad gets so pissed when they don't behave because they know better)

2) No ones about the pregnancy the last thing I want is them telling the grandparents about it.

I told my boyfriend I'd go with a girlfriend if he doesn't want to drop them off at their grandma's place for a few hours.

He's not happy but says he understands. Was it wrong of me to put my foot down?