I just started guitar, and im a pretty good singer... i needa perform. what song?!?

Okay so im 14 and im a beginner at guitar, i just started. Not to brag, but i'm a fairly good singer and i have a good range but im mostly a soprano ( sing higher than lower). I have till August to get the song perfect.( both singing and guitar) There's a particular person i wanna impress and we both love music and glee. I wanna do a song appropriate for kids, its okay if its about love or whatever just not to extreme... i also wanna do a song that's pretty fun or something not too unknown, I DO NOT WANT TO DO ANY BEATLES SONGS. thanks for the help!