Well, that's about time.
Teenagers don't tend to avoid people standing out. They tend to engage with them, either positively or negatively.
Does she need anyone with her to defeat the demon lord? Moral support? But then I don't think the prince would be high on that list...
Just push her through any training you can think of. I'm sure it'll work out. At worst she'll die, but that's not a big loss.
This is a promise of fun times.