Just about got to rotate speed on a taxiway at KMEM. Only had 100 hours, first time in KMEM and only second week of flying a Seminole after getting my MEI. I was to cross one run way THEN a taxiway to the next runway for a taxi departure. I turned right too soon. ATC just walked me slowly to the other side of the airport (Fedex push was starting) and let me take off in the dark in shame. Filed a report with NASA and life went on. Certainly thankful for those guys that night.