HELP!? ASAP... PLEASEE, im a begginer at guitar and i can sing well... i hafta performm..?

Im 14 years old. I have asked this question before but didnt like any of my answers, i want a pretty easy song to play on the guitar... i can sing very well ( not to boast) but i can i have a pretty good range... but im mostly a soprano . i have till august to perfect my guitar playing and singing to that song. I DO NOT WANT ANY BEATLES, or totally unknown songs. im good at miley cyrus songs, and i did bubbly last year with a bunch of friends without any intruments since i didnt play guitar at the time. thers sum1 i wud like to impress and we both love glee, this is for a camp show thing so not too inappropriate. THANKS (: