I teach both the the nylon-string (“classical”) guitar and the metal-string (“acoustic”) guitar. Which one is for you? 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.
This has nothing to do with musical style, it’s just to do with playing comfort. Metal strings will make your fingers sore to begin with – nylon strings are much softer. Nylon strings are also spaced wider apart, which makes it much easier to learn your way round the fingerboard. Another important thing to consider is that the shape of a classical guitar makes it much easier to get into a really comfortable ergonomic sitting position. And for children, it is easy to find good-quality 3/4 and 1/2 size classical guitars – smaller acoustic guitars can be found, but not such a large range.