[JacobIrwin]

Being familiar with C already should help you transition into iOS development. As far as a career, and I am assuming you are referring to the earnings/sustainability aspect... iOS development is like any other enterprise; competition is fierce. Sure, with mobile dev there may be some first-mover points still up for grabs. But certainly not a boatload. Many teams/mobile app companies are already seasoned in development, and some even specialize in creating custom apps for their paying customers.

If you have a great idea (i.e. mobile application) in mind, then by all means, dive in. Without a doubt, users can still benefit from innovation.

Evidence tells us that the majority of successful new startups are produced by developers in the 20-35 age range. Some point to the open-mindedness of younger generations as a reason why. I don't think the "can't teach an old dog a new trick" is always applicable or necessarily true, but then again, it wasn't synthesized from theory.