Complex sentence: Han-Ah is not enthusiastic about her role as captain, but her friends push her to do it regardless of what happens, since before Han-Ah was captain, the boys from the boys' school bullied the girls mercilessly.
Split into simpler sentences: Han-Ah is not enthusiastic about her role as captain, but her friends push her to do it regardless of what happens. Before Han-Ah was captain, the students from the boys' school bullied the girls mercilessly.