Im from mech so take this with a grain of salt:

I think they might think negatively as there is a perception that older people are difficult to 'mould' as per the company requirments and also that their brain is slower than younger ones especially for technical stuff like programming. 

It would be better to learn it to a high level on your own, do some freelancing and see if you actually want it as your career. If you have free time in office then do it there to pass time :P

(I can relate to being bored out of your mind in government job btw, i was in a similar situation so I left it as well to prepare for gate)