For some types, with a radically different geometry, it may take significantly longer before you master riding them. Furthermore, muscles in your legs are used differently, so you will have to take it easy when you take up riding recumbents. Do not start training flat out right away. Keep in mind you have spent years riding your upright. During the first month, the riding will not be as slick as normal.
Recumbent riding is suitable for all ages.
There are riders of four years old, and also those who start at seventy. These companies have been founded by real recumbent enthusiasts, who build their machines by hand or in series, in a quality that is on a par with, if not better than, the products of normal bicycle manufacturers. By using modern techniques and materials it is now possible to 'fly' over the water at high speed, on hydrofoils. Water-HPV's are significantly faster than Olympic standard rowing shells. In this field, large prizes have been offered and won.