Oh for fucks sake.
A heavily pregnant woman at a wedding does not steal any limelight. I was 39 weeks at my sister's wedding. My entire
family all went on a health kick and slimmed down and toned up, looking gorgeous on the day and there's me with my fat football face, sausage fingers, cankles and
massive belly in the middle of them. My sister, the bride clearly stands out as being gorgeously radiant in those pictures Just as she was the centre of attention on the day, as the bride.
Granted, I got a lot of "oh, when are you due?" questions and lots of jokes about not going into labour in the church /dance floor but that was all. Mostly I was sitting with my feet up in the corner watching everyone dancing and enjoying a drink and OH not even able to have a pint in case we needed to dash to the hospital at any point during the weekend.
I stepped down as a bridesmaid - though I would have managed on the day, just about but I would have been exhausted for days. DM insisted I did and to be honest, she was quite right. Sister was absolutely fine with me stepping down, just as she was over the moon for me finally getting pregnant and just laughed her head off when I told her my due date was 7 days after her wedding. The only thing that pissed her off was that she would be on honeymoon when I had my baby.
My family has it's issues, but FFS, anyone saying NOBODY can get pregnant /be pregnant at what is essentially a family party is a nutjob. That is literally trying to control someone's birth choices.
So stop being fretful about the news. Do NOT be apologetic. Be proud of your pregnancy. Shout it from the rooftops if you want. If they step you down from bridesmaid or even as a guest, that is shitty but says more about them than you - and this baby is far more important than being a guest at their wedding.
The only caveat I would add is that you should ideally only announce early to people you know would be supportive and kind to you if the worst happened. These two creatures don't sound like they would and could easily say something awfully cruel to you if something went wrong - so for that reason alone, I would be waiting until as much into the second trimester as I could. DM is a blab so I only told Bride-sister when I was 7 weeks, as she knew I was attending the fertility clinic, but everyone else we only told at 17weeks when I could no longer hide a bump.
I vote for not telling them at all, and let them figure it out themselves. Why share lovely news like that with two people who are guaranteed to say something nasty to you?