Age? And how strong are you. Fact: if your not strong enough your body will hold yourself back becuase it knows that you aren't strong enough to support the strain put on your legs while falling towards the plate.
Also, you don't have to push off. Think about it your on a mound you lift your front leg your body is so offbalance you can get tremdnous speed and momentum without even pushing off. Just fall towards the plate. Its hard and you have to train your body to do it.