Elena detected a little bit of defensiveness in his words about Charms and DADA. She wasn't going to say anything because everyone was aloud to have their own opinion on life. So if she said how his opinion was wrong or tried to explain what she meant, she was taking away his free will. So all she did was nod her head in understanding.
She nodded, Elena was not a pure blood who had to deal with someone else deciding who she was going to be when she was old enough to get a job. Elena was grateful now she was who she was and had her own freewill to do what she wanted when old enough to. "Well that's great."
He asked what she wanted to be and she wasted no time. She knew who she wanted to be when she was older and her parents were supportive. "A healer, I like helping people."