Hi I started c25k in my late 50s, but gave up with winter approaching - cold starts and lack of motivation I am sure I am not alone. It is wonderful if you can complete this course but there is nothing specifically magical about being able to run 5k. Its all about keeping active and fit and enjoying yourself in the process.
Instead I joined a gym where I run but usually stick to about 2.5k along with about 45 mins of weights, rowing and cycling. I do run an occasional 5K to prove to myself that I can now do it (but if I am honest it is boring).
This is not meant to be a negative post. My point is find something you enjoy and do not get despondent if the course seems to much. Just take a bit longer over it or try out other types of activity. I gave up as I just don't enjoy long runs in the cold! But I am I hugely fitter than I was. Now in my 60s I can enjoy long tennis rallies and still feel fresh while my opponent needs a rest (before I felt shattered after about 5 returns) and I recently cycled the 155 mile coast to coast trail between Whitehaven and Sunderland over a few days and loved every minute.
Keep fit and have fun!