I'm not sure if this is an opinion question or not, but if so:
I think it took so long to grant women suffrage because it was a strange concept to many, and women were seen as insignificant compared to men, and that their only purpose was to stay at home and complete their duties. The general opinion was most likely that women were incapable of voting, and were too "uneducated" to vote, so many were opposed to the idea.
