Not that I should worry but what should I wear?!

So, I was invited to DH's best girlfriend's bridal shower next weekend. Been feeling kinda down because i've gained some weight since the wedding, nothing major but enough to make me feel

Now, the shower is at a super posh place in the meatpacking and now I just found out that DH's ex will be at the shower also. (Ex from HS but still, I've never met her and will be meeting her for the first time with girls that have all known each other for YEARS!)

So, my question is... what should I wear? Was thinking something like this.


Thoughts?