Opinions please..

Nice looking bag! It does look kind of big on you...but that's not necessarily a bad thing. Big bags are in. ;)

Can you take a pic of you wearing it with the shoulder strap - I thought that was your main concern...
 
It's hard to tell with the cropped pictures, but it seems large on you. There's large and there's HUGE, but I guess it's all about personal preference. As I said in a prior thread it's a gorgeousssssss bag, but now that I see it on you, I honestly think it's too big. My vote is to exchange it for the City.
 
It also comes down to function. Or were you going more for the look?

Part Time is supposed to be a larger bag...so yes, naturally it will look larger! However, if you don't carry that much around then I say stick with a City.