So I hand delivered a few of my save the date cards (as it was only a walk around the small town I live in).
I knocked on my friends door and no-one answered so I posted it instead. 2 weeks later I still haven't heard anything.
We went for a drink with a group of mutual friends so I asked her then if she got it and the only reply I got back yeah - "oh yeah I did thanks"
Aibu to think she could have acknowledged it?