What guitarist do you want to be ?
If are new to guitar decide between Acoustic or Electric guitar. Think about the music you want to play. There is no truth in starting with an acoustic guitar first. They are nearly always physically harder to play. This is guitar myth no 1.
This is best for strumming, accompanying singing and finger picking styles such as folk and old style blues.
The image above shows two types. The steel strung acoustic is the type to get. The spanish or classical guitar is really for classical or flamenco music. The nylon strings and wider neck distinguish it form the steel strung.
What type or size of acoustic guitar should I buy ?
People come in a variety of sizes so do guitars. I suggest finding the right size and shape of guitar for yourself. Scale length alters how far you need to reach out along the neck. Body shape for instance a jumbo acoustic guitar may be too large for you if you are ft 6''. For an acoustic guitar the distance from where the elbow reaches over the body to the sound hole is critical. If you struggle to reach over the guitar. Wrong size. Is it balanced? Guitar should not be neck heavy. General comfort. You are going to be happy spending hours sitting with this instrument on your thigh. Visit a guitar shop for advice and try before you buy.
The image below gives standard sizing for guitars.
The electric guitar
This is best for rock and blues, metal ,country, lead guitar rock'n'roll,jazz
Just like the acoustic guitar a comfortable fit is essential for the electric too. The profile and shape of the bottom of the body where the guitar rests of the thigh can be problematic again try before you buy.