Hindi tuition since class 3, and she scores in the 90s. Grandmother says stopping in class 7 is a mistake

She scores in the 90s. The tuition is two evenings a week, and she says the tutor just goes through the school workbook with her, which she can do alone. My mother thinks dropping it in class 7 is a mistake 'because Hindi gets harder'. Harder how? Nobody can tell me. Has anyone dropped a language tuition at this stage and regretted it, for an actual reason?