DS1 is growing out of his toddler bed. As their room is small, I'd prefer bunk beds to two singles but he only turns five in December. Would that be old enough for the top bunk? He's not a fidgetty sleeper and never falls out of his current bed which has no bed guard. I just have reservations as some of the bunk beds I've looked at say the top bunk isn't suitable till the child is six.