I'm 5'7'. What size of golf clubs should I purchase?

Your vertical height as a measure does not have too much bearing on your club length.

A wrist to floor measurement would help better than height alone, but then a player gets into their individual posture by tilting at the hips, softening the knees, holding a good T-Spine position (or not), all making a difference to the length and lie the club should sit at address.

From here the swing is in motion and body shape changes again into an impact position. The most important position of the club during the swing is at impact.

Quite simply when looking at a club’s “size”, it has to allow the centre of gravity of the club head to match up with the ball during impact.