Welcome to TFL first off. Second... slow down a tad, young feller. Take a breath. Use a comma or a period once in a while.
Get to the library and check out CJ Chivers book The Gun
Read up a bit.
Start buying magazines now!!!(snicker... if and when you can find any) Ammo too (snicker, snort... when you can find any)
THEN, once the panic buying is over and you have saved up tons of money, have read up a lot and now own a few magazines and a few hundred rounds of ammunition, look up Saiga, Arsenal and AMD65s, heck even a WASR or PAP.
You need to decide now... 7.62x39 or the skinny russian 5.45x39 in your AK? This will be a constraint you need to determine. Hole size making devices you want to send downrange.
Point to ponder. SKS, cheaper than most AKs, same round as the AK (only in 7.62, not in 5.45) install Tech Sights... shoot an Appleseed or two. Keep saving for that AK (Arsenal converted Saiga).
Ah to be almost 18 soon... again. Lucky you sir. I do recommend Chiver's book and his blog. Nice punctuation he uses.
Hopefully you and/or your parental figures have a friend or three who own an AK or two to take out and "familiarize" yourself with? Hopefully?