An acoustic guitar is a guitar that uses only acoustic methods to project the sound produced by its strings. The term is a retronym, coined after the advent of electric guitars, which rely on electronic amplification to make their sound audible.
source : http://en.wikipedia.org/wiki/Acoustic_guitar

TS your Kapok guitar is an acoustic. The instruments are either acoustic or electric. Kapok as Monsterface mentioned is just a name of a brand. As Music Mania mention after a while your fingers will develop callus. It does not matter if you use nylon or metal stings. Just keep at it. If you find that you like to continue playing guitar, then buy a better guitar. Kopok is cheap. It is a good one to start. If you lose interest in the instrument, you have not waste much money.