All are very good points! However, when I tried the large on in the store, I am pretty sure it was stuffed. So maybe that had something to do with it seeming so bulky? At any rate, I just decided to be difficult and go with the large. Katie was extremely helpful and answered all my questions. She said that if I didn't like the size of it, I could return it once again, because they are holding the medium one for me.
I'm torn between the 2 sizes just because, at certain angles, the bag looks good on Lindsay and she's just a little bit taller than me, and I do like large-ish bags. And also, I didn't really get a chance to look at the large on myself in the mirror because I was in a hurry. I only held it for a brief second.
Anyhow, it's a hassle, but it's the only way to know for sure!

What can I say, I make a big deal out of everything!