I have met people from all walks of life on Regent. Postmasters, teachers, prison guards, entrepreneurs, flight attendants, engineers, trophy wives, pharmasists, doctors, to name a few. I have found very few people who try to "put you in your place." I met a woman a couple of cruises ago who, in a manner of minutes, informed me that they have a house in Palm Beach and another on the Cape; I moved away and decided that there are a lot better people to talk with. When I feel that I am being " evaluated" so I can be "put in my place;" I answer the eventual question as to what I do with a simple: "I am a collector. I collect cans along the side of the road until I have enough to book another cruise." It sure gets a cold shoulder.
As for your feeling at ease on a luxury line; you have to decide that yourself. I think it was Eleanor Roosevelt that said "no one can make you feel inferior without your consent." I lived in Asia for a while. The service culture in Asia is so important that the staff from Asia try real hard to please. The luxury lines are "no tipping" as service is already included; just like in most of Asia. Let them do their job; don't worry about sitting there and taking advantage of their skills. Just never demean the staff. That is one of the worst things I have seen on a ship. Truthfully, I saw it worse on Costa than any other cruise.
Luxury cruising is about space, service, food, and exploring; in some order. It is never too late to start seeing the world. My dad was 71 for his first cruise and 72 for his first luxury cruise. Since then, he has seen a good amount of Europe along with cruises in the Caribbean and west coast of USA. The world is a wonderful place. There are seven continents and 195 countries to visit. In most places, the locals will make you feel welcome. Go for it.