Should I announce my pregnancy on my boyfriend’s mom’s birthday

Ok so I recently found out I’m pregnant with twins (yay!) my boyfriend and I are super happy and excited even though this pregnancy wasn’t exactly planned. We’ve been trying to decide if telling his parents on his mother’s birthday would be a good idea. Like maybe put the ultrasound pictures in a birthday card or maybe put two onesies in a box and have her open it…

the problem is I’m not 100% convinced that his parents reaction is going to be one of excitement and joy 🥴 like I said this pregnancy was a surprise but we are adults. I’m 22 he’s 26, we both have good jobs (though I plan on quitting mine in June, long story will elaborate if asked) we have good credit, we each have a car, we rent a three bedroom duplex, and I have a decently large amount of money in my savings account.

The reasons I think they might be unhappy are the fact that my boyfriend and I aren’t married, my job situation, and the fact that I was planning on starting college next year 2023 (yes I know I’m a little late to the game) his parents are really good people they love me and I love them and they even had their first child at 22 as well. Our twins will be their second and third grandchildren and first babies in the family in 11 years.

I know we have to tell them at some point I just don’t want to “ruin” his moms birthday and make everything awkward if they don’t have a positive reaction.

What would you do?