If this woman is attracted to you despite the great age difference, you have to be suspicious on her motives. Perhaps she is trying to be seen as more mature by being with you. Or she wants to play housewife with you since you already have the things like a house and steady income that the friends her age don't. Things may be great for awhile but what happens when she wants to hang out friends her age and they hit you up to buy them beer? Are you ready to go to booty clubs with her? She may grow out of this phase and want someone her own age and then you might have a messy divorce on your hands. Remember that people at 18 still have a lot of emotional evolving to do. Think about how much you changed just from 18 to 21!