You should be happy, not worried!
Comparing your plant to other peoples' grows is not helpful, there are an infinite amount of variables involved, not least the individual plants unique genetic expression, which means each and every seed has its own way of growing and no two seeds will ever grow the same.
If this is a photoperiod plant, it may be worth cloning, due to its rapid early growth.
Remember too, 18/6 is optimum, any more light is not warranted, nor any more productive.
Cannabis does need to "sleep" and 6 hours of "sleep" is about the healthiest amount.
Hope this helps,..............
Organoman.