Uchi no Yuusha-chan Tachi ga Level 99 ni Natte mo Shoshinsha no Yakata wo Sotsugyou Shinai Ken Nitsuite

Mina the brave, Yuliere the knight, Lily the wizard, and Shano the monk. They are a quartet of girls who have yet to graduate from the novice's house, but they are still aiming to become great adventurers who will one day leave their mark on history by traversing unknown lands and defeating mighty monsters...!!! Four "beginners" who always run into unexpected troubles and fail their graduation quests. But what the girls didn't know yet was that as a result of their continuous attempts and failures at the beginner level quests, they had accumulated a tremendous amount of experience, and before they knew it, they had reached level 99! This is a story of four novice girls who are actually the strongest at the maximum level 99. (Source: Dengeki Bunko, translated)