The melody of Happy Birthday Sweet Sixteen by Neil Sedaka runs 440 notes across 67 bars, 5:51 long in G at 100 beats per minute. The tab sits almost entirely in the first two frets, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? Happy Birthday Sweet Sixteen chords and lyrics.