My dress dilemma

I'm going to an event tonight that requires me to wear a nice dress and now I'm stuck trying to decide between two different ones.

I borrowed the blue dress from a friend. I almost wouldn't even try it on because I kept insisting that it looked much too small for me. Luckily, she's a good friend and she convinced me to take it home and just try it. I couldn't believe how good it looked when I put it on last night. Royal blue is the perfect color for me. The black dress is one I already own and have worn before. It's cute, shiny and comfortable.

My issue with the blue dress is that it's much more revealing and form-fitting than I'm used to (and it would require some undergarments that I don't currently own). If I wear this dress, I feel like I'd definitely be saying, "Wow. Look at me! I've lost almost 100 pounds and I look good." While that may be true, just thinking about it is causing me anxiety. I've written many times before that I have issues when it comes to thinking about people looking at me. On the other hand, wearing this dress would be a huge step in my journey. It would be a good opportunity for me to look in the mirror and see how much I've changed in the past two years. But the black dress has it's pluses as well. I feel confident wearing it and I'd probably be much more comfortable in it.

Of course, there's a third option. I could just go shopping today and buy a new dress.