I've never taken a formal guitar class (just started at GuitarTricks), but play many instruments, including a Baritone Uke. As someone with a good baritone voice, who likes to sing in th Key of D, I know that there are thousands of songs that can be played with forms of D, A, G, and C. Nashville was built on this. That's about all the Rolling Stones knew when they started playing music. You might have to throw in an Em, but that's not a challenge to learn at all. Why not try a few songs? You'll have to find your voice, and what Keys you need for it, but it usually only take 3 or 4 chords to play and sing. If you want it fancy, then you need to learn many different chords.