Well, I usually like men about 10 years older than myself.....I dunno.....maybe it's the whole 'father figure'. If people are truly in love, then who cares.
However, in this religion there are definitely alterior motives for many 'younger' sisters marrying 'older' brothers. Case in point is one in my old Hall. She had been married to a guy and had a son by him. All was fine, but then her hubby took off several years ago and got DF'd. Even though she got alot of sympathy, it's a well known fact that in this religion, single sisters over the age of 20 are viewed either with suspicion, or just plain ignored. The only way you can change this is by pioneering. So this sister went on Mothers Allowance for several years and pioneered until her son turned 18 and she got cut off. Since the religion frowns so much on improving yourself by way of education (especially for a woman) she moaned loud and long to anyone who would listen about having to work for a living and did nothing to try and improve her situation. Then, one of the elder's wives died. This guy was 20 years older than her and it was a well known fact that he always had a roving eye for younger women. Anyway, they were married within the year.
Why did she marry him? No doubt for financial reasons (she quit her job the day they got engaged), but also for the social status. Not only was her hubby to be an elder, he became the PO which meant she would go from being an absolute nothing in the congregation, to being The First Lady. Does she love her husband? I seriously doubt it. She married for social and financial reasons.