The first thing you need to decide on is what kind of music you want to play.

Acoustics are very versatile and suit the majority of musical genres and styles. Rock, blues, fingerstyle, flat-picking. Electric guitars are similar in respect to what you can play, like the acoustic it suits the majority of musical genres and styles. Rock, blues, fingerstyle, flat-picking. Electrics are designed to be used with an amplifier.

Classical guitars use nylon strings (gut strings) and are designed to play classical music, a disciplined style of play. If you want to play classical, it is highly recommended to seek the advice of a professional before you buy.

Guitars, in general, have many differences, be aware that acoustics, in particular, come in various sizes. Consider if you would prefer a used guitar vs a new guitar. The most important thing is to choose a quality guitar which sounds nice and is easy to play. Nothing is worse than a crappy cheap and nasty guitar which does nothing to inspire the player. Such a guitar, particularly if you are learning to play, will turn you off playing the guitar.

The bottom line, seek the advice of a professional or a trusted guitarist who can help you choose a guitar that will suit your musical tastes and desired style of playing.