As a still fairly new player myself I would say handle a few different guns first. I bought a vk47 after playing with a borrowed ak my first game. I replaced it with a g36 about two months later and now its just gathering dust. Though you might want to look at AKs and G36 variants because they use the glorious version 3 gearbox and if you ever have to make a repair it will be much less stressful. An M4 gearbox literally drove me to drinking once lol.
If you know the enemy and know yourself, then you need not fear the outcome of a hundred battles.
If you know your enemy and not yourself, for every victory earned, you will also suffer a defeat.
If you know neither the enemy or yourself, you will succumb, in every battle. -Sun Tzu