Education is not like the filling of a pail-
It is like the burning of a fire.

Like a moth is attracted to a flame, education and knowledge attracts all.
One of the sole purposes of education is to spread knowledge- as this helps in increasing both the receiver's and the giver's knowledge.

Education isn't limited to only certain sections of society, nor does it have any age restrictions. anyone, be it a person as old as your grandmother or a person belonging to a lower caste- education is meant for all.

But, due to the omnipresent pressures of society, elderly feel embarrassed of their illiteracy and do not wish to start learning due to fear if shaming by the society,
It is important to teach the masses that there is no shame in being illiterate- you must have the will to want to educate yourself
That's what really matters.   

I hope this helps you.