It's very hard to tell until you have the bag actually on you. I am petite too -- about 5'3" and sometimes even smaller than size 2 and I rarely wear heels, yet I find that some things that are not supposed to work on someone with my specs can work on me because of the way I carry my weight or different proportions (I am short waisted and have relatively long legs). It also depends on what you are wearing and the color of the bag itself, how much it stands out. The weight of the bag, though, is another issue. No matter what your size or how good it looks, if the bag is too heavy it might not be very pleasant to use, and putting it on your shoulder regularly could hurt your back or affect your posture.
As for being in mid-40's, of course that is not too old! I too am approaching mid-40's and there are very few things I won't wear simply because of my age.
As for being in mid-40's, of course that is not too old! I too am approaching mid-40's and there are very few things I won't wear simply because of my age.