Hi sommar, welcome to Cruise-Chat! Congratulations on your up-coming cruise! The only stairs you will encounter will be if the elevators are jammed, then you will end up walking down the stairs. If you're doing the self-debarkation, get an early start to avoid the elevators being crammed. You have all these people, with all their luggage, trying to get off at once. Many times, we've just taken the stairs. The terminal will have the escalators and elevators, they too will be crowded, but doable.
Best wishes for a fantastic cruise!