Buying a dress from Amazon

So I’m not big on shopping online but I see all these beautiful floral dresses and I just have to have one. So thankfully, my cousin is getting married nxt month and I have an excuse to order one. Anyone who shops amazon or has bought a dress give me a little insight on experience and how their dresses run?

Here are a couple dresses I’m looking at

And here is a picture of me and I am curently30 weeks pregnant if ou would like to tell me which dress would look good on me. I am bustier on the top so looking larger on top is something I want to stay away from.

Thanks in advance!!