"People around me don't know that I'm doing porn," said Valerie, a 43-year-old divorcee and mom from the Czech Republic who's starting things off with a bang by getting ass-fucked in her first scene at 40SomethingMag.com. Will they ever find out? Probably not. Most of the women who model for 40SomethingMag.com keep their little secret unless they want the secret to get out. Valerie works in a post office, so she probably doesn't want that secret to get out. But if she sees some of her male co-workers smiling knowingly at her today or tomorrow, they might know something. Seriously, how hot would it be to know that your sexy, mature co-worker did porn? Or your sexy, mature boss? Back to Valerie. She is a swinger who loves to go to parties near her home in Prague. She's also a nudist. She loves anal sex. She loves young guys. "My last one was 19 years old and very exciting," she said. Her sexual fantasy is a threesome with another woman and a man. She's had sex on a…