No, young drivers usually do not have a shorter reaction time than older drivers, since older drivers almost always have more experience behind the wheel.
It is the brain, not the foot, which determines how long it takes before you apply the brakes when something unexpected happens on the road in front of you. The time it takes is called reaction time and is determined by your reaction ability – the better reaction ability you have, the shorter your reaction time.
Readiness for action, a defensive driving style and high risk awareness combined with a lot of experience are crucial for a good reaction ability. This is why experienced drivers aged between 45 and 54 statistically have the best reaction ability.
As the ability to react deteriorates with age, drivers over the age of 75 statistically have the worst reaction ability.