Millennials have been slow to enter the ranks of homeowners, thanks to the last recession and the housing crash that caused it. Now, as they age into marriage and parenthood, they are buying at a faster pace. Many, however, are regretting it. Nearly two thirds, or 63 percent of millennial homeowners surveyed by Bankrate.com said they had regrets about buying. That is more than any other age group and nearly double the regret rate of baby boomers.