I am 10, between about 1.3m to 1.2m, weigh 24kg and I haven t had any major illnesses, apart from being knocked out for a few seconds (I think) after a fall when I was around six or seven. I don t get thirsty, even when my friend, who is the same age as me, was extremely thirsty. I m also really thin, with not much muscle or fat. Is this dangerous? If so, what can I do?