AITA for announcing my pregnancy at my sister's quinceanera?

So the title pretty much says it all but I'll go into a bit of more details. I (f29) am pregnant with my third child with husband (33) we hadn't planned on telling anyone at all tbh as we didn't want to make a big fuss as we tend to keep to ourselves. (We don't hang out with family much)

Well my sister had her quinceanera and I was already 6 months pregnant, it wasn't super noticeable but when I went to take photos with my sister I put my hand on my belly discreetly. (I didn't think anyone was watching as everyone was eating and we were off in a corner)

So as I walked to my table to sit down and continue eating my aunt a couple tables away started yelling "J are you pregnant?!" I was a bit mortified as I didn't expect anyone to notice and said yes because I didn't want to lie...

She then proceeded to get up and run over to hug and congratulate us not to mention stated telling everyone who didn't over hear the conversation that I was pregnant and how happy she was. My mother than came over and started telling everyone that she knew and couldn't tell anyone because I wouldn't let her which was true.

Afterwards my other sister was already wasted by then and started yellling "why didn't you tell me first!" And so much more. Honestly didn't want the family to know but I also didn't want them to find out at my sister's event! I had people I didn't speak to in years coming and asking questions and getting a lot of unwanted attention.

So reddit AITA for announcing my pregnancy at my sister's quinceanera?