Kepler, I'm also new to this, and my first session with Mistress Koi two weeks ago was great. She put me at ease, and gave me the opportunity to let her know that there were certain areas that I wasn't ready to explore. I saw her again last week and will continue to see her in the future.
So, I'd say, definitely go for a session with Mistress Koi, and just be up front with her about your expectations (and limitations). If you have no specific idea of what you want in a session, let her know that as well.
By the way, my guess is that the other mistresses at this group will be equally good.