Well as someone else already said, you are going to get our wish lists. But what is wrong with that?
As a youngster of 25, here is what happened to me. I "bought" my first gun at 17, it was an SKS (I highly recommend, they are cheap, and the ammo is cheap). I already had numerous sporting rifles since I started hunting at age 6, but the SKS was my first actual rifle. I would recommend an SKS or an AK. They are cheap, fun to shoot, and ammo is cheap.
Now just because you get one more gun doesn't mean your shooting days are over. As soon as you hit 18, you can buy all the rifles you want. I haven't bought a firearm in at least a year (don't get married or buy a house until you are pretty much building your collection), so from about age 18 till age 24ish, here is what I did. I know how have over 20 firearms, a complete Dillon Precision reloading setup (RL 550B), and all the accessories (I used to have a $1000 gun safe at my parents house, but when I moved into my new house, they bought it from me and I was supposed to use that money to buy a new one, it went towards the downpayment on the house! :banghead
. Here is the rough order I bought them in.
Age 17
SKS
Age 18
M1 Carbine
Age 19
Taurus PT92C 9mm (parent had to buy it for me)
Age 20
Colt 1911
Mosin Nagant Model 44
Another M1 Carbine
Age 21
M1A
Glock 27
Age 22
Ishapore MKII .308
Remington 700 VS in .308
Age 23
Another Ruger 10/22
Yugo Mauser
Swedish Mauser
Age 24
Mosin Nagant 91/30
Remington Model 870P
Schmidt Ruben K-31
Age 25
Model 1903 .30-06
Model 1903A3 .30-06
M1 Garand .30-06
As you can see, your firearms spending might not be much now, but as you get older and slowly make more money, you will buy more firearms. I was going to college from age 18 to age 21. All of those firearms were bought on a students meager earnings. From 21 on, I bought more firearms because I didn't have a house payment, a car payment, and I spent my money wisely.
You have a rich and prosperous firearms heritage ahead of you. Try not to be in too big of a hurry. Start small, enjoy what you have. As you get older and earn more, spend more. The only other thing I can say is even though at this time reloading might not be the forefront of your thinking, eventually you need to face the fact that you are going to want to reload. I used to be content buy my ammo in bulk at gun shows. At age 22, I saw the light and started reloading. What a wise choice in my firearms career.
Whatever you chose, enjoy it.