Maintenance will be performed on the forums for the next couple of days. Expect some downtime.
So, she is 189 cm and is in middle school? That would make her about 14 years or so. According to a wikipedia article on height by nation the average height of a Japanese female is about 156-158, so that would make Hiki over 30 cm higher than average and since she is still in puberty she is likely to continue to grow. I can understand her concern for her height, but when you are that tall at such a young age there are usually some medical condition causing it.