I actually googled "Carrie Hillcrest" before I named myself that. As far as I can tell, I'm the only one. So if some other lady starts calling herself Kerry Hillcrest or whatever, you can bet I'll be peeved.
I am afraid, however, that you are not the first and definitely not the last DeeDee/DeDe/DiDi/etc.
It's a very common name, in both the provider and civilian worlds. If you're concerned about identity confusion, add a last name or an adjective (DeeDee Smith or Deelicious DeeDee, for example).