When I tell my fellow Marie Claire editors I'm a "Samantha" today, I'm not referring to the publicist in Sex and the City 's leading quartet. No, I'm one of the many millennial women aligning myself with my favorite American Gir l doll—whose signature uniform is now available in adult sizes through a Hill House Home collaboration . For many women in my generation (millennials), American Girl dolls were the cornerstone of our growing-up experiences. We spent the '90s dressing the brand's foot-tall dolls in historical garb and reading their dedicated chapter books ; when some of us got older, we planned to pass them down to our own daughters. Now, we're being invited to get back in touch with our inner child through Hill House Home 's limited-edition collection. Prints from two of the original "historical" dolls, Samantha and Felicity, have been reworked into adult-proportioned Nap Dresses. Both are available online today, May 4—and are already selling out.…