Older Elite Knight Is Cute Only in Front of Me (Manga)

Synopsis

I the strongest prodigy of the kingdom, Haru (16) have been assigned to the Knight Order. My surperior in this knight order, where the strongest of the kingdom gather to become the elite, is Karen-san, a 29 year old single woman. Usually she is a feared and noble... The Karen-san that does things like, inviting me to her room, acting like a spoiled child or showing special facial expressions only towards me is just too cute...!