People tend to generalize however from what you said you should have no problems with your career. The over 40 issue in my experience is that programmers either get burnt out on doing the same thing for a long time, or refuse to keep up with current trends. You will get people that say they have been writing shell scripts on unix for the last 30+ years, well thats great, but what else can you do since not every thing is a unix shell. The fact that your actually looking to improve your knowledge makes you even more marketable and desirable as an employee. people that just want to do the same thing over and over again till they die will not make it in todays IT world.