@Abedeus well, she herself is like in her early twenties, not sure if that is that much of a gap. I know a recently divorced couple where the gap was 23years, that was a huge difference in power dynamic, here it's barely noticable, considering he's taking the lead most of the time and she constraints them both from any sort of skinship.
I read somewhere a recent study which claims that due to the change in culture in the west during the past thirty years psychologically people that are younger than 24years are basically still teenagers.
Can't really link the source, but there was the data to back that up.