Weddingbee boards

I was watching The Big Bang Theory and realised I have a similar material and I loooove Penny's dress. I want to almost duplicate it, but was wondering if it was wedding approriate. I want mine to hit just at my knees and have wider straps. Penny's happens to be a halter type dress as well, and mine won't be, just plain straps.

Please ignore the quality of the picture, I was print screening the show so I could get different views. Also, I would likely wear a cardigan like Penny, and black heels. I have wedge heels that are more comfortable but I think that would be too casual. Anyways this is the dress:

The invitation says nothing about black tie, or casual. The wedding is at 4:30 in the afternoon, and it simply says "Dinner and reception to follow". Thanks for the help!

Oh good! I was worried because the venue doesn't have many pictures and everything I searched I had a hard time finding photos with guests in them. Thanks!