Need advice

Sooo back story...

After years of trying and fertility we are expecting our second in the beginning of December.

My sister in law is due two months after us with their first and my Husband's kinda step mother's daughter is due about a month and a half behind me. The "step mother" wants us to do a three way gender reveal party for all 3 of to reveal at the same time. I find out at the end of the month what we are having.

She keeps on insisting both are going to find out a few weeks after me so we should do it all together despite the month and a half different due dates.

Am I being crazy for not wanting to wait and do it with them?!