I think a point that is worth mentioning is the groundschool at the more mature age. If you have been out of education, or have not had to constantly learn new stuff during your career you WILL find it harder to remember the groundschool subject matter.
I ahd exactly that problem. I understood everything but could not remember it. I spoke to a friend of a friend who is a neuro surgeon and he explained the reason why. The neural connections in the brain which act as the 'wires' to the storage (memory) break down without use, ie if you have been out of education for a long time. When you go back to learning for the first time after several years absence it takes several months for these connections to be re-made, ie to use the full capacity of your memory which has been ticking over only using a small fraction for 'x' number of years. Sure enough, after 3 or 4 months I started to remember the material much better and after 6 months, when I sat the exams the vast majority was there.
So I hate to admit it, but there maybe some truth in Michaelknight's not too diplomatically put initial posting. However, the problem is not insuperable and just another hurdle put in front of the (sometimes more determined) older Wannabe.
PP