What would changing your room do for sea sickness? Do you get motion sick when riding in a car, out on a small boat or flying? If no, then you will probably not get motion sick on a ship (regardless of cabin), unless you talk yourself into it.
If that is true, will you be avoiding all decks, shops, theatres in the front of the ship?.
Yes, motion may be a slight bit different in a Bow or stern cabin, but I hold to my first point. There is no reason to believe you will get seasick (motion sick) unless you get motion sick on "land".
When are you sailing out of Philly? We are also sailing the bermuda cruise on horizon out of philadelphia in july. we've never cruised celebrity and never cruised on a smaller ship, but I can say that if you are prone to motion sickness, you should prep yourself beforehand. We've sailed enchantment of the seas (RCI) and the Star Princess...one a medium sized ship the other large......both rocked a tad here and there, but nothing to worry about.