CAMELOT FANTASIES

I wonder if anyone can help me. I've got a guitar & all the books to learn how to play it. Does anybody know how to play without getting sore fingers. Dad had to buy me a teenage one as my arms are too short to hold an adult one properly. I've had it a bit but Dad told me the sound coming out of my mouth sounded better than the sound coming out of the sound-hole of my guitar & I was to sing for him because I sounded lovely & he would learn how to play guitar.