I performed an experiment similar to see if switching really works in the monty hall problem, It didn't.

Question

I recently learnt about the Monty Hall problem. Theory says you should always switch since probability of winning then is twice. But I feel why won't probability be redistributed and be half for each door..once one door has been opened. So I performed an experiment. I was Monty and my sister had to choose. We did 18 rounds and the result was shockingly surprising. 2 times out of 9, switching won the car, 7 times it failed, and amazingly, 2 times out of 9, not switching won the car and it too failed 7 times. Is there something very convincing in favor of switching?