my grandma still treat me like a child.she can't imagin---gr

My grandma still treat me like a child.She can't imagine ___ grown up.
答案是me,是作宾语,所以要用第一人称的宾格形式,grown up作宾语补足语
如果你认为是my,多半是受中文翻译来的意思影响的吧