20Her age difference with Anakin
When Padmé first met Anakin, he was only nine years old; five years younger than the 14-year-old queen. While that wouldn't be a big deal once she's 35 and he's 30, it's a bit creepy at their age of marriage.
When you marry the person that you practically babysat, who followed
you around like a little puppy dog while you were a teen queen, it's at least a little bit weird. Had Ani been the little girl and Amidala the young man, people probably would have been outraged over the marriage.