ONE: stop announcing that your 12 years old. it's not an excuse for anything if that's what your using it for. And also, your supposed to be 13 to join the forums ;-)
TWO: your helmet looks decent, it just needs a little attention to detail. Try taking your time and cutting out smaller detailed shapes, rather than a couple big strips of cardboard. and like TheBlue said, layer the cardboard in some spots to give it some depth/detail