Big baby!!!

OMG just got back from my 30 week scan and baby boy is 4.3lbs already! If the 1/2 lb a week theory is true he’s going to gain at least another 5 lbs! I really thought they were kidding about having a 10lb baby considering our first was only 6lb 11oz. Hoping that they’re sizing is off, I really want to be able to labor naturally but over 10lbs they recommend a c-section. Anyone else been told they’re baby was big but ended up natural labor and smaller?