I teach both the the nylon-string (“classical”) guitar and the metal-string (“acoustic”) guitar. Which one is for you? Well, in the long run, that will depend on what sort of music you want to play – but if you are a beginner then you will do yourself a big favour if you start with a nylon-string guitar (Why? - see FAQ).
Guitars can play melody, or chords, or both. For younger pupils it is generally better to start by playing melody and learning the notes – chords will sound much better later once the fingers of the left hand have become strong and supple through tune playing.
The classical guitar is almost always played with thumb and fingers. The acoustic guitar can be played in this way too, but is also played with various types of plectrum or "pick".
For a typical child beginner, 7 is a good age to start guitar. Younger pupils will progress much faster, and have much more fun, with ukulele – and will lay a good foundation for guitar at the same time.
And now for something completely different ... !
For more information about guitars see the FAQ - or try these links to some fantastic players: