Older women, younger women it's all the same. Loyalty has no age limits when it comes right down to it. An older woman could cheat on you & bounce a lot faster thinking she won't go through it again because of her past experience of being in a relationship. A young chick can get buckwild after awhile or she may be a grateful woman & stay loyal. Only time will tell.
In the end, regardless of age if she really loves you she'll stick it out through thick & thin and try to make it work.