Diana Pallas-Smith, or Diana Smith-Pallas, is very good at fighting.
She's not as good at teaching, because that means she has to put her kinesthetic intuitions into words - but when it comes to walking someone through weapons to see what actually suits them best, she doesn't need to be the best teacher. She can just watch. Watch, contemplate, understand, integrate. Observe, orient, decide, act.
...Lila moves weird. And sure, her fellow student of the Light hasn't been down on the practice fields before - that's always been more her own thing; you need to understand how things handle in order to craft the best tools and there's something about a good fight that gets her blood pumping, even though it shouldn't - but there's just something a little bit off about the way Lila handles the practice weapons. Like she's - got half-rusted instincts from another body, or something, moving in ways that could have been effective rather than awful if she'd been half a foot taller - which is obviously impossible but still not obviously false. It's weird.
She's seen Ser Mattan knock his own rust off a few times, and while it looks like the one kid her age in the village is kind of just stumbling around with new weapons she's never held before - it still has her watching intently, because reflexive actions are where a façade is most likely to slip.
(She doesn't know why Ser Mattan thinks she'll need to know ranger tricks, but he's teaching her, so she's not going to complain about it.)