While growth plates close at this time (~13-15), in preprofessional training it's more usual to start from about 12. Basically,one's feet need to be strong enough to protect growing bones from permanent damage, thus safely starting pointework has more to do with having enough strength from previous training (2+ years) than fully closed growth plates. For more information: https://www.ortho.wustl.edu/content/Patient-Care/3496/Servic...