hi!  hope i got your name right!
 
well, my experience with ferrets has been such - age is not really that
big of a deal.  an adult ferret has usually gone through its biting stage
and with a 6 year old that might be a good idea.  the baby's nipping is
not any worse than a puppy or really playful kitten but a bite is a bite
and sometimes little kids freak out.  i do agree (from my experience
only) that the females are a teeny bit more aggressive than the males.
all of my so-called biters have been girls.  but i don't think you should
worry about the age.  i also have a male who was severely abused and bit
the owners a lot (out of terror, i am sure).  they gave him up, i got him
expecting him to be a problem.  he is one of the sweetest animals i have
ever lived with.  he will sit still and let me clip ALL of his nails,
front and back.  this is practically unheard of!  he will kiss me to get
down when i was repeatedly warned to watch out for severe biting.  the
only time he has ever bit me was when he wanted my sock (which i was
wearing) and got my toe along with it.  he was mortified and scittered
away so quickly i am sure he thought i was going to kick him.  the point
of this is age doesn't really matter and check out the animal when you go
to get it.  if s/he is energetic, lets you pick him/her up and doesn't
bite but wants to get down to play around - go for it.
 
and as far as smell -- i hate to say it but all animals smell.  that's
nature.  but (once again, my experience only) the thing that really
smells is their waste products.  don't worry so much about keeping the
animal clean as keepting his bedding and litter box clean.  that will
eliminate (hahaha) more than 85% of your odor issues.  and anyway,
ferrets smell LOVELY.
 
have fun and good luck!
[Posted in FML issue 1121]