I'm 25 and consider myself very well-versed in C (though I still have to consult the C99 spec from time to time). When I was learning to program modern computers around the turn of the century, it was the only "serious" language for writing desktop apps (I had recently "graduated" from VB4). I then refined my skills over the course of my electrical & computer engineering degree and a short stint in the EE industry, where it's very much alive as THE language for microcontrollers (and last I heard, a variant called SystemC was (sadly) replacing Verilog and VHDL for use in ASIC/FPGA design).