Is getting good grades eveything?

Ok, so this may sound like a rant and it probably is, but I just don't understand the mentality my peers and parents and teachers have that smart students are only those who get very very good grades. I'm an average student but in a case of (mis)fortune, I was selected to be in the top cl of my school. I go to a science stream school by the way but in the past year or two, I began to realise my pion is more towards writing than handling lab apparatus. But, I stuck it up anyway. I don't do extrmely bad in my tests. The recent mid-year exams, my results were not great but I didn't fail anything. I got 2Cs. 2 B and the rest were A. I am taking 10 subjects. Unfortunately, in my cl, that's not considered good enough. And now my Mum is saying that I haven't done the best that I could (which I truly did!). I think I can do better but it was still hurtful that my mum said what she did. I was expecting she would compliment me on what I did well rather than patronising me for I what I didn't. This is my last year of school and I am hoping to go to a good university. But at the same time, I feel, it is as if I am only striving for other people's sake rather than my own. I want to be a writer when grow up but it seems everyone is channeling me to do otherwise..It's depressing.