I'm 5'7 and 130 lbs, and I'm a 34C. I normally would've gotten a size Small for this dress, but since the Medium was the only size in stock at the time, I just bought Medium instead. It's not big enough to return it, it's just a bit loose in the back, but I probably would buy the size Small if I could buy it again. Overall I love the dress though, it's SO cute! Also, just to clarify, when I mean True to Size, I mean it's true to size for medium, but if you have similar measurements as me, I'd recommend getting the small.