You got 15 years experiene writing C code, good luck finding a "whiz kid" who can do it better than someone who's been doing it for that long.
You said it yourself, C isn't going away anytime soon. Stick to it as your bread and butter.
If you want to learn to program for Android/iOS, that's great, but do it as a hobby. Employers nowadays want 10 years experience on a tech that's only been available for 5 years (yes, it's that crazy), so by the time you get up to speed, the market will have already moved on to the next shiny thing.
You started with "It's 2014..." What will you do in 2025? Like I said, when it comes to your bread and butter, stick to what you know best.