hey i'm only 16 and wasn't diagnosed until i was 14 and of course i wanted to be an astronaut, football player, or racecar driver, it's what little kids do, especially boys. i now know that the astronaut thing is definatley out (i stopped wanting to be one when i was like 10 because i learned that because there are no toilets in outer space they wear diapers lol) and the others are unrealistic, not impossible, but unrealistic, i would suggest that you keep encouraging your child regardless of what they want to be, when i was diagnosed i learned that the military was out of the picture (that is what i wanted to do at the time) and it upset me but i knew there wasn't anything i could do about it so i just sort of accepted it, i would think that others would do that as well, don't rain on their parade with, oh, you can't do that because of your cf, it doesn't do well with their self esteem, but as they get older, if they still want to be a firefighter, sumo wrestler lol, or astronaut, go ahead and tell them they can't do that, but suggest something like it to not completely ripped out from under them, this is starting to ramble so i'll shut up, hope it helps