Surely there must be more than two horses worth looking at? I'm not particularly fussy when I go looking for horses but I do start off with a sensible height range, price range and age range (and colour range but that my own quirk!) What is the mad rush as well? You need to set out a clear idea of what you are looking for. Wouldn't you be better off looking around further afield and taking a bit longer to look for a horse a better size for you? All these small women with great big horses might feel fine but they look like a pea on a mountain IMO. I reckon you should wait for something with similar credentials about 16h but its entirely up to you.
I think it depends on what the horse is like to ride. I'm 5'6" and my new boy is 16.3 but he's a big boy. You really need to get your legs around him and if I was a couple of inches shorter I really don't think it would work!
Had a try and see what youthink is all you can do really x