Not knowing your location makes it difficult to suggest a rifle and that combined with your age makes it real difficult. My overall take is that to purchase a long gun (rifle or shotgun) legally you must be 18 years of age. If you have a parent that is OK with you having a rifle then they will need to purchase it for you.
That said I would suggest a gun show and look at surplus military like the Mosin Nagant type bolt action rifles or any of the mouser rifles or maybe an old British Enfield rifle. Even with a $450 budget you will be hard pressed to find a US military type rifle (unless you get lucky). The Mosin Nagant, Assorted Mousers and British Enfields all are popular surplus rifles. Another pretty nice rifle is the Spanish FR 8 Mouser chambered in .308 if you can find one out there. I would start by doing some homework and reading a little then visit a good gun show. Shop wisely as the same gun can have several prices at a show.
Also, to reiterate, make sure this is fine with your parent(s) who will need to approve and buy the gun.
Finally if you want to forgo the military rifle thinking there are some fine .22 caliber rifles that make a great first gun and are cheap to shoot. More food for thought.