No offense here, but your 15 years old. Your not fully developed yet, and probably won't take to the heavy recoil of the heavy mags very well, esspecially for a first rifle. I would suggest starting with a .270 Winchester, a 7mm-08 Remington, or a .308 Winchester. These are all long range rifles with enough power to kill an elk. But where are you hunting? Is it more likly you will be hunting in the trees where shots under 150 yards are the norm? If so, I would suggest my old stand by and get a 30-30. They have a bad reputation, but will kill the biggest elk that walks if the shots are close. Also, they are easy to handle, are light weight and fast pointing, and are not too expensive. Buy that rifle, a cheap loading set and load Nosler Partitions and you are set for deer, elk moose whatever. Good luck.