Both my wife and I are 70+. We've been RVing for a number of years and have had 3 motor homes and are on our second 5th wheel in retirement. First we would suggest buying a good used unit, you will save money and in many cases the bugs are worked out of them. Second we have a good quality 5th wheel now but what we don't like is the one ton truck we need to pull it. Ride is rough, hard to park and use for sightseeing and shopping. We wish we still had our Class A motorhome pusher and were pulling a car.
You will lose money, but not as much as with a new rig.
It's great life and we do enjoy traveling and the lifestyle of RVing.