My daughter has just had her 5th birthday in october and her height is 123 cm. i'm kinda worried that she might be way to tall for a girl.

Bit tall: Ultimate height depends on several factors, mainly genetic, also how she did earlier, was she always on the 95th percentile for her age, what about her weight too? Kindly refer to this link as a guide, and consult a pediatric endocrinologist, good luck http://www.cdc.gov/growthcharts/data/set2clinical/cj41c072.pdf

Taller than most but: If your daughter continues on her current growth curve she'll probably grow to be about 177-180 cm (5 foot 10-11 inches). It's taller than most girls but isn't that unusual (though perhaps less common in Indonesia then the US) and it is a matter of judgment if that is "way too tall." But nothing can really change this- some people are short, some are tall. She can still be happy and healthy!

Context...: You are giving one point in time which places your daughter at >99%; however, is this in line with how she has always grown and the height of the family? It appears she is going to be tall, true. Likely the exact height she is supposed to be so not TOO tall (a judgement, not medical fact). Follow up with pediatrician and check out her growth chart trends to date.