[support] difficulty moving drupal from folder to root?

I am new to Drupal, and I'm setting it up for a 1000 member organization's website. Drupal will run their website as well as using CiviCMS (thanks for the recommendation!) for our membership needs. Because they have a current website, and I can't take it off-line while I develop the Drupal one, I've set Drupal up in a folder. Now I'm beginning to worry about how hard it will be to move all this to the root directory??? Am I worried about nothing? How difficult is it to move from the folder to the root and how many things can go wrong? Am I asking a really stupid question? Thanks, Tina