I knew I wanted a classical guitar, not a folk one, and it didn't take much research to find that the Yamaha C40 was the obvious choice, but even so, buying sight unseen has proved to be perilous. This guitar is indeed the real McCoy - superb for the price, beautiful, immaculately built, but be warned, it is HUGE and solid and heavy - in particular, the neck is like a railway sleeper! I was amazed at this.
Admittedly I had been playing the ukulele for a month, so that may be causing a distorted perception of it. But I happily messed around with friends' guitars when I was a teenager and don't remember having any problems - I'm guessing that's because they had folk guitars with narrower necks.
Stats: I'm 5'6" and guess my hands are smallish, but I was beyond grade 8 on the piano 30 years ago, so at least I know my hands aren't useless, and I am going to persevere with this guitar philosophically [added: since I wrote that, I've grown to like this guitar more and more]. If you are in any doubt about how big you are, then don't buy a guitar on the internet until you've been to a shop and tried a couple out for size (possibly with an experienced guitarist by your side to tell you what's too big and what isn't).
Please read the discussion. This review does need rewriting. In short, there is only one size of classical guitar - the rest 3/4 etc, are for kids.