If she's short on time, what should she definitely do quickly? Regardless of whether Crin and Ishaza are trustworthy?

Learn magic. Learn more about the world. Those are the things that gives her the the most additional options, and the most sense of what those options are. Lies about the state of the world will likely be easier to slip by her than ones about magic, given her increased learning speed. But any errors that were slipped by her would be more likely to cause major problems- for someone who didn't have her categorical immunity to most of the negative effects of miscasting. Yeah, magic seems- the best thing to go after learning quickly.

"So. One of my secrets. I learn quickly. Far faster than reasonable, if not faster than would be possible for a once-in-a-millennia talent. I say this now because I couldn't possibly hide it from you if you taught me any substantial amount of magic, and I suddenly feel an urgent drive to learn."

"Huh." Crin raises an eyebrow. "That's certainly unusual. Would you like a lesson now, then?"

"I would. I'm concerned by the possibility that that comet bodes very ill very quickly."

"Well enough. We can do some very basic Shyish shaping exercises."

She nods. Probably getting through that phase of your magic career takes long enough normally that she won't in fact graduate beyond it in one night, even if she's learning twenty times faster than Crin did.

"Thank you."

Crin settles down cross-legged. "Since you have windsight, you'll be able to practice more easily. Watch as I shape, then repeat with the small amount of Shyish I send you."

She nods.

She will focus very hard on what Crin's doing and do her absolute best to do exactly and precisely what Crin is doing and not grab more Shyish than is eventually sent her way.

The Shyish reacts quite docilely; her will seems to be strong enough to break its natural tendencies to gather and clump.

Lovely.

It probably helps that she's manipulating so little of it, but she didn't actually know that was an option.

Crin guides her through some simple motion exercises with the small clump. 

It'll take a few hours to get the motions down, even with this small amount. There's an element of reflex to it. 

The sense of urgency fades, over time, and she is left with the sheer joy of learning.

She always did love learning new things, and now nearly all of the difficulty has been stripped out and only the good side of learning is left.

Also. She's learning magic.

Magicmagicmagic.

Still, she endeavours to focus, and not end up distracted by how good a time she's having learning-

Magic!

-distract her enough she accidentally almost kills herself or something.

After a few hours' practice, Crin starts to lightly perturb Alethia's Shyish while she's doing the exercise. Once disturbed it gets... a little messier, harder to control cleanly. But its natural tendencies to flow and clump remain. 

This actually makes it easier to keep herself focused enough she doesn't get distracted by how fun this is.

It's an interesting exercise, pushing back against Crin's disturbances in exactly the right ways to ensure she doesn't cause problems. The switching point between clump and flow makes the entire system a bit more complicated and difficult to predict, but she think she's getting the hang of it.

Then Crin will continue the exercise at this level for a few hours more. 

And Alethia will continue to learn, soaking up as much skill as she can.

Eventually Crin calls a break as Alethia's control starts to fatigue a bit. Even skilled wizards can't wield Shyish forever.

"You're not lying, you really do learn fast." She raises her eyebrows.

Oh, good, whe was the tiniest bit worried that she would somehow not actually get to have that.

"Indeed I was not. Entirely reasonable to consider the hypothesis, though."

(She has received a good grade in magic student!)