Yes and no. Both. There are many ways to look at this question. If yoga is purely a physical sport or exercise (which is as far from the truth as it can be) then yes you should to have some prior experience in Asana practice. If we look at yoga, purely from the physical point of view, then yoga has many exercises: stretches, twists, back bends, splits, arm balances, etc., which are also found in gymnastic, ballet, calisthenics, body weight training, aerobics, various forms of dance, and many other sports and fitness activities. Therefore, in our opinion if you have any experience in any of the above fields then you already have experience in Yoga, even if you have not done those stretches or twists on a yoga mat or in a yoga studio.
If we look at yoga from the spiritual point of view, then yoga is a lifestyle, that includes many elements; practicing cleanliness from the inside and on the outside, truthfulness, compassion, non-greediness, non-possessiveness, contentment, love, concentration, conscious breathing, awareness, mindfulness, etc. We are sure you must have tried to practice these qualities from time to time in your life, irrespective of the degree of success you achieved. Therefore, if yoga is a lifestyle as the yogic scriptures teach, then you have already been practicing yoga for some time, most probably since the time you were born.
Once you have reserved your spot on the course we do recommend that you start practicing physical yoga postures as much as you can,and read a few spiritual books recommended by us so that you can get maximum benefit of your time with us.