Keeping tile clean is really dependent on two things. How hard is your water (water and calcium deposits) and how often you clean it. Personally, with you nearing your golden years, while I love the look of tile, I would consider the plastic stall. It is easier to keep clean, less risk of cracking, and is less slippery when wet than some tiles are.
Not to mention, as you age, you may wish to have a coordinating plastic/folding stool or chair to sit on, and it will blend in or be less noticeable with the plastic.
Just my .02
