Dangerous Baby Gate

My family recently moved into our new house. We have a staircase now and so installed a tall, metal baby gate at the top of the stairs. The baby gate is great at preventing the toddler and baby from coming down without help, but my 7-year- old is another story. She cannot open the gate, even though we’ve tried to teach her. Yet she is constantly climbing over it in the middle of the night. We have tried everything to have her stop doing this. It is unsafe for her to do this and it needs to stop. However, we are at a loss for what to do. Any advice??