Welcome. It's never too old to start. Bear in mind that even the best guitar players in the world were usually smokin' after spending a few years from 15 - 18 doing nothing but practising the guitar. You've heard the 10,000 hours theory? It's merely a matter of how much time you put in. Admittedly it's a lot harder for adults to find the time, but it's possible to become very familiar with the instrument at any age.
But your son's in a better position. Congrats for taking the time to figure out what might be a really good option for him.
I don't know this seller personally, but I would heartily recommend this deal - depending on your location. The Yamaha Pacifica is probably the best bang-for-buck beginner's electric ever, and the Roland Cube is a pretty good candidate for the same accolades in an amp:
http://www.guitarforum.co.za/classifieds_old/yamaha-pac012-guitar-roland-cube60-amp/
These guitars are the kind that many keep and modify, rather than flog, if they get serious about playing and decide to buy a more expensive electric.