While killing slimes for 300 years, I became the MAX level unknowingly

While killing slimes for 300 years, I became the MAX level unknowingly summary:

For that reason, I decided to live a slow life at a house in the mountain as an immortal witch of with a figure of 17 years old. The main source of income is to defeat slime inhabiting nearby to acquire magic stones. I sold this at the Guild at the village. Besides, I made medicinal herbs,Appreciated as “The Witch of the Highlands” and lived with respect and trust. However, as a result of continuing her life to beat Slime for 300 years, experience values acc.u.mulated too much, and unknowingly became level 99 the world’s strongest witch . The level 99 witch now works together in the village with her dragon-girl apprentice in moderation, while helping everyone in the village.