There are some great points here, and everything is true! Picking your date is stressful, and it's upsetting when people try and tell you what to do and complain about the dates you want. We went through the same thing, my MIL sent us her vacation calendar and all the trips she was taking for the next 18 months, the very first week we got engaged! We had to plan our wedding around her vacations!! That was a hard pill to swallow. Of course we wanted her there, how could she not be? But telling us we had to work around HER????? I was so mad. It still kinda stings, to be honest. I really wanted to get married on a few dates, Valentine's Day being one of them, I fell in love with the idea of getting married on Valentine's Day, but b/c of her we couldn't. Anyway....it all worked out in the end. But yes, it sucks and it's hurtful when people try and take over.
The ladies are right, your day will be amazing and beautiful and you'll be so overwhelmed with love and support from the people who are attending, the others who can't join you will be in your heart, and everything will be lovely My very best friend in the whole wide world and my MOH couldn't attend my wedding b/c she had a baby, and it was devastating but of course I understood, he was too young to take to Cuba and much too young for her to leave him with Daddy and come by herself. (it's a good thing he's cute!) It just happened that she and I had two major life events happening at the same time, and she couldn't be there on my special day. But I made the best of it, we had a little cardboard cut out of her face and we took pictures with her, we took video for her, and she sent me an amazing gift for my "something borrowed" so she certainly wasn't forgotten about.
It's hard when you want everyone to be there, but sometimes it just doesn't work out. It will be your special day no matter what, and you'll be so focused on getting married, you'll be so in love and giddy, in that moment, nothing matters but the two of you