Quote

"“Mrs. Rochester!  She did not exist: she would not be born till to-morrow, some time after eight o’clock a.m.; and I would wait to be assured she had come into the world alive before I assigned to her all that property.”

I honestly think she is, in a way, being pressured into marrying Mr. Rochester. Yes, she is in love with him but in there last chapter Mrs. Fairfax was telling Jane how their relationship wouldn't stand. I thought that since her past with her cousins made her think that she had to do things the way everyone thought it should be done she might wanted to take a stand.
(Ex: Financially supporting herself)