Well, I grow Crepe Myrtle "zuni" in NJ (zone 6b/7a depending on which zone guide you use), and I never really experience die back on my crepes. Of course, a southern exposure can't hurt as they love summer heat too. I would do some fact finding though on your particular variety and its ultimate height and width. Maybe someone can suggest a minimal safe distance from the house. In my prior home, I had planted a hybrid-variety crape myrtle on the south side and it grew so fast and vigorously I was always pruning the thing. Eventually, I had two rapidly growing sprawling trees and they both had to be cut down because they were too close to the house. It was a shame because they had beautiful lavender flowers from August through September. My current crape are growing along a fence and far from the house.

Natchez is one of the larger of the hybrid Crapemyrtles, developing a large frame quickly and attaining heights of 25 feet or more. I have no idea if it would thrive in your location.