I agree with Giga.
Etiquette says that chowing not occur on the first time around with a girl. You should know her body and mind a bit more before going there. And, absolutely...fresh and clean is the best. If she's been walking around all day and is now at a youth hostel at the end of the day...she's probably getting a bit musty--from her perspective, I'd guess that you are, too.
Anyway, my girlfriends have always just showered and then invited me to give oral sex. At that point, they're all fresh smelling and such. If asked earlier in the relationship, I generally indicate I like trimmed quim.
Bottom line, though: you gotta like what your woman tastes like. If you like a woman's taste and can spend considerable time giving her oral pleasure, both of you are going to be very very happy sexually.
Considerable time...one sex partner would have me giving her oral sex for between 30 minutes and an hour at a time. She loved it. I loved her taste....it was magic.