There’s plenty of people with small hands who play the guitar. Nine times out of ten smaller people confuse the terrible awkwardness that comes with the first week of playing the guitar and mistakenly think it’s because their hands are small. Again, you’re teaching your hands to do really strange movements here. Imagine going to an advanced yoga class having never stretched before, that’s basically what you’re doing.
I have heard how giving you are in so many respects of music schooling and I must say that I am impressed. You remind me of the pure idealism that we had in starting Apple. If I were young, with time, I'd likely offer to join and help you in your endeavours. Keep making people happy, not just in their own learning, but in the example you set for them. 
I was lucky enough to meet Justin at the Guitar Institute during a summer school in 2004, and to have some private lessons with him afterwards.  He was the teacher who kickstarted my guitar career and persuaded me that I was ready to join a band.  That was 14 years ago and many dozens of gigs later.  I’m now just finishing a degree in Popular Music Performance.  Justin's online lessons are easy to follow and he has a manner about him which makes you believe that you can achieve.  Where he demonstrates songs, I have found his versions to be consistently more accurate and easy to follow than those of any other online teacher.  On this website you really will find all the skills and information you need to become an excellent musician.  Many thanks. Ian.
Practice fretting the strings. The frets are the metal strips that run perpendicular to the strings that mark each note. To play a note, press your finger down between the metal strips, not on them. To say that you're playing the third fret means that you place your finger on the string in the gap between the second and third fret. If you hear buzzing, move your finger away from the lowest fret and closer to the higher fret. Hold the string down firmly so that it only vibrates between your finger and your strumming hand, with the tip of your finger doing the pressing.
Wow! This post really seems to have helped a lot of folks get started with the guitar. It has been read by – I kid you not – millions of aspiring guitarists. Thank you! As many of you have noted in the comments below, no, I’m not selling anything here related to playing the guitar. My motivation to write this post was that musicians, and especially guitar teachers, can often make learning the guitar sound way too hard. It’s actually easy.

Intermediate Guitar Class - Open to all ages, from age three to one-hundred sixty-three, but an audition or permission from the instructor is required. This class is intended to be challenging. Topics covered may include movable bar chords, song forms, repertoire development, fretboard mapping, improvisation, and other advanced techniques. New classes start every month and may be repeated as often as you like. Cost is $85 per month (4 hours).