Tammy: She’s very strong, she has lots of practice, and she’s Weiryn’s daughter. I also don’t think she uses the English (Welsh, really) longbow, which is six feet long, but the smaller version.
The recurves used by the Riders are also hard to string and draw, but they train on them. Crossbows are really hard to draw (most modern crossbows use a kind of lever to pull the string back to the trigger, as did many of the medieval ones).
If they didn’t take trouble to master, they wouldn’t be interesting–that’s my thinking! But in any case, Daine is Weiryn’s daughter, her aim being another legacy from him.