I was an ACSM HFS certified specialist for 3 years before starting school. I worked as a personal trainer, so it was advantageous to have that certification when I worked in that industry. Will it hurt? No! However, it may not serve any significant purpose either. Why, may I ask, are you interested in that certification specifically? There are a number of organizations(ACSM, NSCA, NASM) that offer certifications. Are you interested in personal training, fitness, strength/conditioning before starting school?