Absolutely tell them!! I am a coach, and it is very frustrating when parents don't give me information that is vital to helping me teach their child in the most effective way. I had one student with serious medical issues which I didn't know about until she had to take 4 months off from skating because her health had declined (oh, I guess she really *was* too tired after one round of simple stroking exercises...), another who was almost completely deaf, which I didn't know about until I mentioned to her mom that she really didn't pay attention very well in a group class ("yes, you have to make sure to look directly at her when you talk so she can read your lips"), and another with a learning disability which I didn't know about until I mentioned to her mom that I had to make sure to demonstrate every thing several times before she got it (no wonder she took months to memorize moves patterns).
In all of these cases it would have been very helpful to know beforehand, rather than go through the frustration of trying to figure out how to teach this kid who for some reason wasn't responding well, and I had no idea why. Please talk to her future coaches so they can start off on the right foot and can work with you and your daughter in the best possible way.