Gender reveal!

We are getting to know the gender of our twins next week. My husband’s cousin says they are all curious and excited to know and I should immediately announce it in the family chat. I didn’t respond to that. In the family Chat is my SIL and her Husband which we are just cordial but nothing beyond that. We didn’t announce our pregnancy to them either. Actually, I don’t really care to announce it right away. In a way I would like to enjoy to keep it to ourselves. Maybe I’m being petty, but actually I would like to have control of when and what I would like to share my privacy! Is this too much to ask?