Jane Eyre is born into privilege, but is placed in an orphanage as a child. She gains an education at the orphanage and once she reaches an age when she can leave the orphanage, she is hired as a governess for Edward Rochester. The shift in her status from dependent orphan to paid employee represents one shift in her social mobility; but even more significant is the fact that Rochester is wealthy and lives in a grand mansion (Thornfield). The fine house means Jane will live in comparative luxury while she is employed there.
After a few weeks Rochester and Jane fall in love and he proposes marriage; this represents a third shift in social mobility. However, upon discovering that he is still married (to a wife who is legally insane), Jane leaves Thornfield with nothing but the clothes on her back and makes her way across the moors, starving. She is rescued by St. John and his sisters, but working there as a teacher is not really a step up from her status at Thornfield. St. John offers to marry Jane so she can accompany him in his missionary work, but she refuses, preferring to marry for love rather than propriety.
When her guardian dies Jane receives a sizable inheritance, dramatically altering her social status again, giving her financial autonomy. However it is her eventual return to Rochester (whose wife perishes in a fire she lights herself), and agreeing to become his wife, when she at last attains the most significant alteration in her social status, becoming a happily married woman to a gentleman of means.