Imagine a girl her size firing that thing she would probably fly from the recoil
Actually not as bad as you might think as a heavy weapon absorbs recoil by being harder for the impulse of firing to accelerate, muzzle breaks also help by directing gas backward they effectively pull the weapon forward when fired counter-acting some of the rearward impulse, and if it's fired prone from a bipod (and with this weapon there's no other real option) some of the force will also be directed into the ground.
At 20 kilos with a muzzle break and some springs in the buttstock as well the recoil probably isn't that hugely worse then say an M82 Barret.