Well, now that I've read the next chapter and am reminded that this is, after all, a wedding fic, I'm not surprised that you included a different wedding in one of the flashback scenes (or is the 'backstory' the main story and the pre-wedding scenes just the flash forward parts? But I digress....). This was a pretty romantic chapter, and it's always nice when Brian gets to spend lots of time with Meg, and always more entertaining when it's somewhere a bit public. ;)
It was a good sign that they both couldn't stop thinking about potential future commitment toward each other. And, of course, wonderful that Brian is so attached to Meg that he wants her there. Should be fun seeing what the 20th anniversary year looks like in your AU!
I feel like there's lots more story to develop, and I hope we get to see many more pre-engagement episodes.
Great work!