It looks a little on the big side, but I still like it a lot on you. I adore the 35 size. I am a few inches taller then you though and live in heels so any smaller looks too small on me personally. (I think anyway).
I think a 30 would be great on you but if you need to pack a bunch of stuff, go with a 35 again!
It looKs great on you! I'm also 5'4" and originally bought a speedy 35. I loved the look of it but found I did not have enough stuff to fill it, and even when I did, it was very heavy on my arm. I now have 2 speedy 30s, and they work for me
It looks good on you. I'm not quite 5'6" and my first was a Mono 35, at the time the DE only came in 30 and I just had to have it too. Love them both but definately love the oversized look of the 35 more.