What Does It Mean That My Sister Will Become My Sister in Ten Years?

[Youth Campus] [Warm Everyday Life] One ordinary day, as an older brother, I was accidentally knocked unconscious by a medicine bottle while playing with my sister. As a result, I was in a coma for ten years. Ten years later, her body almost stopped growing. When she woke up, her sister had grown into a girl taller than herself. In other words, my sister is now my sister!