I think that it's still fine. Just keep your accessories casual.
I agree. It's nice the wedding is in the fall and you picked a season appropriate outfit. If it had been a summer wedding and this issue come up, there is a bigger difference to be worried about with an outfit for a summertime wedding I think.
^^^ Yes, nude heels or sandals will make it more understated. If the accessories are small and limited and closer to your skin tone, it can be more "garden party". A small black clutch with nude heels would be OK too.
I don't think it's too dressy at all. I actually think that because of the print, it's more of a daytime dress than evening- where dresses tend to be more solid colored and bejeweled. I also agree that it's better to be overdressed than underdressed, especially since you are family.
Okay, so we have a 100% consensus that yes, the dress will be okay! You all make great points in terms of recommended accessories, how I may have been overestimating the "dressiness" factor, etc. I feel much better now and will parade around the BBG with confidence (and with subtle shoes, bag, and maybe some small gold pearl earrings). Thanks to all, very much appreciated!