It's completly personal preference. Tradionaly speakin they are probably about right but the trend in park skiing has been for pretty small poles. Personally in the park I use a 105 and I'm 5'11 so if you go off that yeah they are pretty long. But they might like longer poles. Best bet is to ski them and then cut them down gradually until they feel right. Remember you can't add length back on so don't cut too much straight away.