I heard a tune from deep down memory lane coming out of your room and just couldn't stay away. That song's from over ten years ago.

Those are your feelings towards this song... and music itself at the moment, right? That's how you should sing it. It doesn't matter what it is that you feel. Just unleash those feelings.

 There's no such thing as a song that can't be played. And one more thing... No matter how worried you may be about your mental readiness or your ability... I think that feeling itself is pure, and that it's something special.