Anyone can learn to play guitar at practically any time and at any age. Choosing the best guitar to learn on is a completely personal decision. At the end of the day go with the one which you feel most comfortable with and hopefully inspired to pick it up and play it as much as possible.
Nylon string guitars are the most common instrument for younger players as the strings are softer on the fingers. The sound of a nylon is mostly associated with classical or Latin music styles however you can play any style on any guitar. Nylon strings also come in a range of smaller sizes to accommodate younger students. ¼, ½, ¾ and full-size (4/4) are all readily available and a music retail professional can assist you with sizing up a student.
Steel string guitars have a more contemporary sound and are the most common style of acoustic (non-amplified) guitars. Steel strings can be harder on fresh fingers; however steel string necks are thinner and with a low action are ideal for any learner. The most common size for a steel guitar is the dreadnought model which are generally too big for smaller learners, however there are common smaller sizes and shapes available such as folk, parlour, orchestral and travel guitars.
Electric guitars are probably the easiest on beginners fingers due to their thinner neck profile and smaller gauge strings. However electric guitars do not build player strength as well as the other models and involve the purchase of other equipment and accessories to get you started. If you are considering starting on an electric guitar, pre-bundled amp and guitar packs are a good idea as they usually contain all the items needed to get you playing right away (guitar, amp, tuner, picks, bag, strap, etc.) Just be wary of getting too distracted by all the gear and focus on getting a good clean sound from the guitar.
The best way to discover which one is right for you is to play all three styles of guitar The most important thing is choosing an instrument that you will want to pick up and play every day. *Please note the strings on each guitar are relative to each instrument and cannot be inter changed at a later date Handy optional extras worth considering - Clip on tuner - $20, Guitar stand $20, Instructional Book with DVD $20 and a Gig bag $50