It unlocks at 20,000 points
You unlock the g18 at level 30, you can unlock the g18 suppressed at level 41.
Yes there is no doubt about it.
no
Not legally.
No, the BF4 Beta is a separate download/installation.
About 25 pounds.
Now
No, you can be any age to play Battlefield 3.
battlefield 3
Go to multiplayer on the main menu
Dice, a branch of Electronic Arts
No you can't unfortunately.