When it comes to investing, Jill Silverstein’s got it  in the bag .  The 35-year-old Hermès hedonist lives by the motto, “If you’re workin’ hard, Birkin hard.” But Silverstein, a luxury real estate agency owner from Chicago, told The Post that her collection of Hermès’ ever-haute, ever-enviable Birkins isn’t just for flashy show. Instead, the pricey purses are a part of her retirement portfolio.  “The Birkin has literally outperformed the S&P 500 over the last 20 years. And, you know, the stock

Tag-uri: Real Estate