As others have already noted, ferret's responses to water depends on if
they want to mess with it, or if they are being tortured with it.  Ours
happily hop in the tub for a drink, but HATE baths.  I've also had them
join me in the shower and in the bath.
 
As to personality changing with age, they seem to start calming down a
bit at about 4-6 months old.  If your ferret was quite young, as you say,
and also sleepy, it sounds as if you got a quite young baby.  I got all 4
of mine at about 8wks+, and the most recent two didn't seem to sleep
terribly much more than their older siblings.  Keepup on not allowing
biting (we bite back at times), and have lots and lots of patience.
 
My most recent ferret monster baby is one week older than my human baby,
who hits 6 months tomorrow.  The ferret was a lot easier to train.  But
then, she's lived a lot larger portion of her life.
 
Liana Winsauer, keeper of
Ron (husband), Robin Thomas (human baby); Neko, Totoro, Akira, and Kogeki
(baby brat), the ferrets; and Kamaria, Friggit, and Mesu, the cats.
 
[Posted in FML issue 0802]