My reply is long, because I got opinions.
Let me start by saying, OMG #11. You look like a million bucks USD$! You really shine in that cobalt blue. I've been half a dozen fancy day weddings in the past 5-6 years, and that dress would put you ahead of everyone except the bride, on the 'dressed up' scale.
My mom has not willingly put on a dress since I was a little kid in the 1970s. But she put on a dress for all of our weddings (four kids). And when I look at the photos, while she looks beautiful, she also looks uncomfortable and ill-at-ease.
If I'm ever crazy enough to have a wedding again, or if I have something fancy to bring her to, I'll tell her to wear what makes her feel great, and her best authentic self. And that's going to be pants, and a beautiful top, and one of her sparkly statement necklaces.
Tell you something else: people get so judgmental and ridiculous over weddings. There is this societal tendency about how everybody is 'supposed to' dress, but most especially the mothers. Society wants to marginalize women when they reach a certain age, and especially at weddings, where you get this weird and ugly little undernote of 'how dare she show out like that?'
Perhaps I am being unfair to your naysayers, but I think they are reflecting back their own insecurity and regret on you.
Marija, you are so absolutely stunning in #11. I feel I'm looking at you, and not a dress, and not a stereotypical image of a mother-of-the-groom. And the bride and groom both like it.
SHOW UP AND SHOW OUT IN THE DRESS YOU ALREADY HAVE AND LOVE. YOU ARE GORGEOUS!
And if you want a new dress, I think you should definitely get #1, and make some occasions to wear it. The lines are beautiful on you, and I love the print! It feels special and unique on you.
I also really like #2 and #3, but they don't grab me like #1 or #11-12. They're reading more "wedding guest" to me, versus MOG. I also really love the Holly Golightly vibe of #6. Drape some pearl strands over it, and you're instant Audrey Hepburn. The nude shoes in #6 look great.
I love the colors in #7, 9, and 10 for you, they make you glow.