Hi Daydreamer. You should be OK on Fjord Deck. As high as that sounds, there are still several decks above you. In fact, it's a great location as you have cabins both above and below you... less noise that way.
Should you feel any seasickness, grab a green apple. I learned this from a crew member years ago, and it's worked well ever since. I doubt you'll need it, though.
Please continue to ask questions...that's why we're here.