Congrats on your new Love bracelet! I'm hardly an expert since I've only had mine a few weeks, but what I've learned is that comfort is the most important thing - especially for the long term. They way your 15 fits you is how the 16 fit me and I opted for the 17 to have more room. I initially preferred the more fitted look of the 16 but after reading thoroughly, posting on here and talking with 2 different SAs, I decided that it is better to have a slightly looser fit - especially for the long term. I plan on never taking mine off unless I absolutely have to, and I could see how day after day the 16 could potentially rub my wrist the wrong way and end up irritating me or being uncomfortable. My 17 definitely moves up and down my arm easily and can turn at the thinnest point of my wrist, but not on it's own. It's also not as loose on me as a typical bangle nor does the movement annoy me. I have gotten more use to it and don't mind it! Having said all that, I think it comes down to comfort for you! Your 15 definitely looks nice just from an aesthetics standpoint, but the marks it left on your arm in the last picture make me wonder if it's digging in or uncomfortable on you? If it feels comfortable on you and you don't foresee the fit bothering you in the future, stick with it! But if you think it could potentially be too snug to the point of causing discomfort, maybe at least go back and try on the 16 again just to see. That's what I did, and it definitely helped me when I was going back and forth between sizes. Again, I haven't had mine nearly as long as some of the other ladies on here have had theirs so not sure how much my advice is worth with only 3 weeks of wear, but I hope it helps! And whichever size you ultimately decide on - enjoy it!