Yes it is possible,

There are no limits and bounds to learn. Learning is never ending process.  It is possible to learn at anytime and anywhere and also at ‘anyage’. Any enthusiast learns from all the sources available.

To code, particular should be familiar with coding languages like C, C++, core java, advance java, python, pearl, web developing etc.  C language is foremost to become a coder. It is basics to all other languages or it helps to learn higher languages easily. To learn coding efficiently one should be upright with C language which is very basic language for coding starting with small codes then learning syntax thoroughly. Then further step is to avoid syntax error then code error, removing errors i.e. debugging (removing bugs), using less memory by writing small code for logics. It is possible to learn by joining tutions or classes or can also learn online by subscription to the particular course on different platforms with certification or free of cost.  As 1 year diploma has a good understanding of cs subject, it becomes easy to learn further mid-level and high level languages.  Age is not a barrier, understanding and good practise of coding is important.  Coding also offer good paid jobs as teacher or freelancer.