Answer:
Never ahead, ever behind, yet flying swiftly past, for a child, I last forever, for adults, I'm gone too fast.
I don't live within a house, nor do I live without. Most will use me when they come in, and again when they go out. What am I?
The shorter I am the bigger I am.
I go around a yard but do not move. What am I?
I reach for the sky, but clutch to the ground. Sometimes I leave, but I am always around. What am I?
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.