Higher age limits are ridiculous in the modern world, and particularly in Ryanair.
Youthful exuberance is far less valuable in an airliner cockpit than maturity and life experience. I've flown with young Captains who clearly have no common sense but have enough hours and SOP adherence to be upgraded.
The idea that there is a training risk inherent in the older candidate is also misplaced. However, if Ryanair actually cared about safety they would be hoovering up pilots with flying experience and paying enough to retain staff.
Apart from the legacy carriers, there is little job security or loyalty, so the value of having cadets and indoctrinating them into a career is utterly pointless. The only counter-argument is that they are so young and impressionable that they will do what they're told without question. Hardly a virtue, hey...