brooms and gemstones [O.Wood]

Rhiannon Vela Duncan was a hard character to describe. However, everybody agreed on one thing concerning the young girl;

she was utterly stupid

and it was a baffling sight to see. Scary even, as she wasn't even aware of it, though most students weren't holding back to remind her each time her tongue spoke before her mind.
Divination always came easy to her. And soon, students were able to see past her silly being and ask for her help in that class. She was able to predict someone's future situation just with their tea leaves or even their detailed dreams.
And the alarming part is that , she was always right about someone's prediction, whether they were pleasant or nasty...
And, with that, she was known as the Omen of Hogwarts
So what happens when the keeper of the gryffindor quidditch team seeks her help about his team's future ?