Sizing dilemma! Did I do the right thing? Please assure me. Or not...
I bought a 2009 (I think?) jacket from a friend's coworker who sold it because she's buying a house, but I'm not sure I did the right thing because I'm worried about the size. It's a 42. I just couldn't resist, and from reading the posts here, I thought it'd be all right, but I'm having second thoughts as it's on its way to me.
I am bigger than I normally am (gotta start running again, haha). I am about 5'3" and a size 6, normally a 4, and pear-shaped. Because I'm out of shape, my arms are bigger than usual. When I do lose weight, I do notice it more on top right away than the bottom. I tried on a bunch of the jacket months ago, but sadly I couldn't remember which ones I tried on and how they looked. I should've taken notes.

I remember trying a couple on that felt tight in the upper back and in the upper arms - I felt like a linebacker! But since I don't remember which sizes they were, that doesn't help. If it's any help, I wear a medium in S.W.O.R.D.
Guesses as to whether the 42 will look all right on me? I don't like super cropped leather jackets. I love the way it looks on Freja here, how it kind of has that "sucked in, curve into itself" fit. Does that even make sense?

I'm obviously no model, though.

I don't plan on layering or zipping it up. I'd like to wear it unzipped with a thin T-shirt mostly. My torso's on the longer side, I have short legs, and a small chest. Haha.
I'm worried because I can't return it, and what if it doesn't sell if I eBay it? It's by far my most expensive piece of clothing, so it's making me anxious. But the jacket is so gorgeous that I just bit the bullet.
Thanks!