When to announce pregnancy

My SIL is very horrible to me and her brother, she told everyone she thought she was pregnant when she hadn't even tested (told me she was 10 days away from a missed period) as a way of getting the spotlight off us for announcing we were going to get married.

Out baby has just turned 1 and we are keen to have another so they have a short age gap and have been trying since my period returned (breastfeeding so we thought it would take years) in May

My question is should we announce at 5 weeks pregnant like we did for our son or wait until my SIL has her moment of spotlight over the birth of her new baby?

I feel like us sharing our good news would be a spall slice of pay back for all the things she has spoiled for us with malicious intent. She really is the sister in law from hell 😭