@KarrotKakes thats actually a valid point.
Or would be if not by what we were already shown by the series.
In the very first chapter the FL was shown as confident and easily brushed off her shyness after her introduction. She also has shown little care for what could be considered intimate affairs, so little there was even an entire arc built upon her attitude and words lead EVERYONE to believe she was having an affair with the second prince.
And Cesar is a war hardnened veteran who has seen his men die, he has killed and even BUTCHERED enemies. Its extremely unlikely no woman ever approached a general even during a war.
And most important. Both are already functional and socially capable adults. I am not saying they both must act like chad and chadette but there is a lot of middle ground between that and act like middle schoolers.
Take Doctor Elise for example. A similar scene happen between the FL and ML with the added difficulty that they are still not married at the time of sharing the bed for the first time. The ML hugs the FL who snuggles on his arms and both fall asleep. Realistic, adult and innocent all at once.