How to respond.. a question for those who have lost a pregnancy

So I just recently lost my daughter at 21 weeks 3 months ago. I thought I was doing ok emotionally but now that the due date is coming up my emotions have come back full force.

I’m seeking grief therapy right now in hopes it helps.

So here’s the dilemma , my husbands cousin is currently pregnant and finding out the gender Friday. Saturday she invited us to a gender reveal party. I just can’t handle it. Just thinking about it right now I’m tearing up.

She had an early miscarriage prior to this pregnancy so she knows that side. My daughter was my third loss.

How do I respond to this? Would it be ok to say “I’m so happy for you guys but being that I just lost my child 3 months ago, I’m not in the emotional state to handle this event” ?? Or something like that?