For every bad thing this manga throws at us, there is an equally great scene like this. It's definitely stronger in its comedy parts, than its military otaku parts. And seeing Rory pouting just makes my day. Hilarious.
No one would have sex with someone that's 900 years old. Similarly, no one (hopefully) would have sex with a 13 year old. But suddenly it's okay if you combine them? Not in my book. That's still either an old woman or a child.