On the zodiac cycle thing, there is a bit of significance to it. Really, just a tiny bit. Even if they were both of legal age, being from different zodiac cycles is the age gap at which other people would get gossipy about them being weird or whatever for going out with someone so much older or younger. Like referring to the older one as a cradle robber, for instance. You know, one of those things where there's no actual problem but people get nosy and want to talk about it.