You'll be so glad you made the move once you get here!
In fact, at some point, you'll probably ask yourself: "How in the world did I ever live and survive in Houston?"
I e-mailed Dave (the ex-Houston guy who now happily lives in Manitou Springs), and I hope he comes back on here to encourage you. As for me, I moved to Colorado from New Jersey in 1997, and let me tell you, it is one of the greatest decisions I've ever made in my life. Regarding the "big city" life that you mention, I highly doubt you'll have much culture shock here, and if anything, the culture shock will be for the better!