I think it's a great idea! 20 years is definitely worth celebrating. You go through so much in that time and know so much more about each other. The fact that you'd still choose each other is definitely something to share and celebrate.
I want a minimalist gown - zero lace, minimal embellishment. V-neck or off-shoulder, as my husband loves my collarbones and shoulders. Probably a sheath or similar slim-fit gown.
This style is having a moment right now, they're very easy to find - I'm hoping that trend continues. I remember when I looked a few years ago, finding a minimalist gown was nearly impossible, and then when I glanced this year they were everywhere. Hopefully I will still have a lot of options when the time comes.
I have already bought two dresses even though it is 3 years away. I couldn't help myself as I really liked both. I don't know how to put pictures up though . Yours sounds like it will be lovely as well. I hope they are around as well when you come to choose one .