What she's specifically going for might be a motivation too. Maybe her brother has xyz disease and she's going to school on full scholarship to be a neurosurgeon or something. A chance of making a difference vs immortal happiness.
The "other responsibilities" is more or less where I was trying to go with the whole college-aspirations train of thought.
I was thinking more along the lines of a family member she's supporting, or a friend she made a promise to.