I walk around my child, me and my siblings. One of us is too young and he is not one of us anymore. All my child does is sit there and wobble every so often, but he is the brightest of us all. I am one of a kind, and none of my siblings are like me, a lot of them are just full of hot air, but I fear the day when my child gets bigger and kills us all. I have been here for some time, but I won’t be here is a while.

Who am I?