Hi lovely,
I haven't had braces myself so I'm not sure how it feels. Why not practice oral on a toy or a cucumber just to see how it feels and see if there's any interference? You might feel a bit daft but who cares! Is there anyone you could have a quick snog with to get feedback? A partner or good friend maybe...
If you really don't feel comfortable with the braces, perhaps think about not offering oral services until they're out. Does it take long? X