Is my friend normal weight?

I have a friend of mine. I believe she is 12-13 I donna... The other day I was helping her with her homework which was recording your growth at home (weight and height). I always thought she was 40-50kg but she's actually 60kg keeping in mind she was 168cm. Is it normal for her age? Is she considered "obese"? She doesn't look it at all but if so I can always start exercising with her...