I think it works in your use well enough. I understand what you're trying to communicate there.
Just because I've read parts of this and we've chatted about dev before, my only crit here would be that you might be over-directing in the script. That can really depend, though, and I know you're largely a solo dev so it may not matter. Did you plan to work with a separate voice director or actors later on?
With a good actor... it's incredible what levels of nuance he or she can add a line. So much of that is shades of grey, though, and a big part of voice directing is guiding/iterating the actor through the exact tones. It's the kind of thing that's very hard to say from the writer's side, sometimes. So I could write (falsetto) or any other stage direction in the script. In some cases, that might tell me a lot, in other cases it tells me next to nothing. That's why actors and directors do read-throughs early in the process. They're looking to see how a scene sounds.
So in this case, putting on my (limited) voice directing hat: it's obvious from the context Catherine is prostrating herself before some kind of god or lord, worshipping. That context probably informs the voice more than (creepy, little-girl voice) does because all you're really doing is calling a trope, here, and little girls can sound creepy in a lot of different ways, some of which my given actor may or may not be better/worse at pulling off than others.
That line's actually short on info, really. The kind of info that only the writer can provide, like why is Catherine so taken with this god? Is this worship sincere or a front? Is she in mortal danger one way or the other? That then starts to give me context so that, instead of trying to tell my actor to do X voice, I can give my actor the right context and then know when I hear the right voice. There may be any number of variable deliveries that will sound right, some might be completely different than you expect. As a writer, you make the director's and actor's jobs easier when you give them room to find the tone themselves rather than trying to dictate a specific, often vaguer-than-you-think tone.