People pleaser needing advice!!

I have a horrible time letting people down. It weighs on my sooooo much!

My office is having group photos taken next Friday. They will be outdoor photos. Forecast shows it will be 99 degrees that day. I am a currently 25 weeks pregnant and not tolerating the heat at all. I REALLY don’t want to do it at all. We had photos done last year which I was in and they were great! We are redoing them since we have new members. But I am really struggling with the thought of being outside for 3+ hours in 99 degree heat while pregnant. OH and part of the dress attire is jeans 😭

How rude would it be of me to tell them I just won’t be there due to the heat?