Read the newspapers. Watch local TV news. You would think Tampa Bay was awash in 20-somethings. We pepper our stories here with references to millennials and emerging hip downtowns hoping to cater more to younger workforces and their urban tastes. Nothing wrong with that. It is accurate. But the additional truth is Tampa-St. Pete is still ground zero for the gray hairs. We'd better embrace it.Tampa Bay's population over 65 years old numbers 18.7 percent — just under one in five residents — making this metro area the oldest among 53 major metros in the United States. So note leading demographic experts Joel Kotkin and Wendell Cox in a recent Forbes analysis. That percentage has even grown from a few years ago when those over 65 here represented 18.2 percent.No other large metro area had a higher percentage of seniors then. None has a higher number now.Welcome to the aging of America, an experience Tampa Bay is previewing ahead of everybody else in a country where the national metro average for over-65's is 13.3 percent.Sure, Tampa Bay may have lots of older folks. But we are not on the latest top 10 list of the fastest aging cities, the up-and-comers with increasing percentages of seniors. Those cities include Atlanta, Raleigh, N.C., and Las Vegas. Some of these cities might seem unlikely candidates to be aging quickly. Denver? Austin, Texas? Odd as it sounds, these hot spots of youth are now attracting the elderly. Both metros are in the top 10 areas that are aging most rapidly."Virtually every part of America will become more senior-dominated, but some more than others," Kotkin and Cox state. Citing census projections, the duo forecasts that by 2050 the number of Americans over 65 will almost double to 81.7 million. Their share of the overall population will also rise to 21 percent from roughly 15 percent now.Metro areas that, like Tampa Bay, already have high populations of folks over 65 are getting a good preview of some of the impact America as a whole will experience in the next few decades. Other cities whose populations already skew older include Pittsburgh (18.3 percent are seniors), Tucson (17.7 percent), Miami (17 percent) and Buffalo (16.7 percent). Others like Cleveland; Rochester, N.Y.; Providence, R.I.; and Hartford, Conn., are not far behind.Why are some places aging faster than others? Seniors are drawn to places that tend to cost less. They are motivated to move closer to children. Many others — think Rust Belt cities — stay right where they are thanks to inertia, cultural ties or a lack of money. As younger people move away from such metro areas, the percentage of seniors who remain inevitably rises.With close to 10,000 baby boomers still turning 65 every day, they've got to live somewhere, right?Contact Robert Trigaux at [email protected] Follow @venturetampabay.