Nope! I lived in Wisconsin, sporting a super heavy midwestern accent, until I was almost 12. I moved to Rhode Island for 5 years, then briefly Baltimore, then back up to Boston for nine. The New England thing (and the mid-Atlantic) never sounded natural to me. HOWEVER, as a child, I believed the midwestern was the non-accent of the US -- after I'd been gone for a few years, I was finally able to hear the accent. It is only through the power of the home movie that I can hear how awful I sounded in childhood.
i was 'born and raised' (southern terminology) in AR and moved to minneapolis/st paul just after graduating high school. working as a waitress there the local men were relentless in making me talk around them just to hear my southernese. without fully realizing it, i developed a northern twang. my first visit home was one year after i moved there and my family was horrified to say the least that i talked like a yankee. when i moved back to AR 3 yrs later it was me that was horrified at how my native folks talked. to this day i am middle road with my accent... i pick up the nuances of whomever i am around. odd.