Thanks!
You're actually nowhere near the end of her route, it's like the start xD
You need high INT score, so maybe equip some Aquamarine Amulets and maybe drink a potion that increases INT score. Reading books gives a bonus to passing her test, though not all books count. Books about, Maths, Physics, Ancient Lore, Religion, etc gives various bonuses to passing her test. You only need to read each book once to gain its bonus. Your Alchemy skill and Artifice skill levels are also taken into account.