Plane Shift is a Seventh-Circle Spell.
There aren't many wizards that good. She once tried to count just how many at Silvermoon, and came away with a blinding headache and no answer, but it's definitely not many. The ones who are tend to be old and strange.
The odds aren't very much on her side. At best, it will be many years before she can see another plane.
But why? Stories abound of people wandering into forests and waking up in Fairyland, or falling overboard and down whirlpools into Elemental Water, or worse things, and many of them are even true.
What happens if, for example, you curry favours and play people off and trade insights and do people's homework and, let's be frank, spend a term dodging supervisions to poke at wards and tripsigns until you can sneak into one of the forbidden sections of the Library and make a bootleg copy of a certain Spell and try to strip it down? What is it, fundamentally? What makes it so hard?
...Turns out, mostly it's the targeting.