。
She is a college student.
Literal
She [topic-は] college-student is.
A textbook X は Y です identification. 大学生 is built from 大学 ('university / college') + 生 ('student'); the same ~生 suffix gives 高校生 ('high schooler'), 中学生 ('middle schooler'), 小学生 ('elementary student'). Note that Japanese 大学 covers both 'university' and 'college' — there's no formal distinction.