Pulling up

I guess crawling isn't enough for one week, she is now trying to pull up on things. She's been pulling up to a standing position when I hold her hands, but now she's taken it a step further. While I workout at taekwondo I put her in her playpen at the back of the room and she has a blast playing by herself. When I looked back today I saw her hands pressed against the side of her playpen and her legs were straightening up... she was almost in a full standing position. She amazes me at how quickly she learns new things.