am I too old to learn the guitar/music? 
plinkplonk: You aren't too old to learn.It is hard (though probably not impossible, given sufficient motivation and practice) to get good enough to play professionally with a late start), but if you plan to learn for the joy of music and playing songs at parties and so on it is very doable. If you practice  (guitar) for 20 -30 minutes daily for a year, you should be good enough to play some popular songs at parties and so on, ideally with people playing other instruments.The key is to regularity (don't miss practice) and focus (be aware of what you are doing when you practice) and not so much short bursts of intense practice.As mentioned above if you can get good  private lessons , go for it. You can teach yourself with books and an electronic tuner and so on, but it is way harder than getting a good teacher. Since your wife is a musician she (or her friends) should be able to find you a good teacher.Good Luck!