Can a 12 year old girl grow 17cm more?

Maybe, but I'm just gonna say now that there's nothing wrong with being short anyway. Girls tend to do their final height lengthening between ages 12 and 15. I'm almost 15, and I don't think I've grown even a full inch since I was 12 (and I'm 5 feet 5 inches, by the way) but it all depends on the person. If you've already started your period, then it's likely that you won't grow much more. But all that aside, 17 cm is quite a bit to grow and it isn't very likely. You might get a few inches, if even that. But in any case, there are multiple body height calculators that you can use to find your expected height range on the internet based on your parents' heights.