Ok i have shot a .22 pistol quite a few times before. Never owned one just shot friends. I've had my mind set to get a .45 ACP XD for over a year now. But i was reading on here where people is suggesting starting out with 9mm first. Why is this? Is there really a need to start there? I know the ammo is cheaper i've just been set on a .45. I have shot tons of shotguns and rifles before w.o starting with the littlest gauge. So really what is the main reason why so many suggest starting out little first?