There obviously is exemptions but in my experience when the student is older than 25 years it will take longer to reach required standards. When over 40 it gets even more time consuming task and I am not talking about required flight hours only. I mean the entire process takes longer to complete. Donīt know the age of student in this case.
However, usually older students are well aware of their personal learning capabilities and intelligent enough to allow reasonable time for safe learning process.
Nikolai