In clarification, her piano teacher does teach a little by ear, but says my daughter is reluctant to sight-read, so she is pushing this area at this time in order to solidify.

From your posts, it sounds like your daughter already has the ability to "listen" and this would be strengthened if she's doing well in competition Irish dancing. With technical basics taught well by a classically trained teacher who is on the girl's wavelength and continued exposure to sessions and live fiddlers, I reckon she'd be well ahead of most of us at 15.

So long as she continues to find it all a pleasant experience.

Cheers, Rowan