It seems like San Francisco is where all the big companies are based, but I'm not sure if I'm ready to move out there. Would it be a bad idea to NOT move there if I want to work in tech?
San Francisco is definitely not the only place in the world with a tech industry. More and more of tech is actually shifting toward decentralization, so that means San Francisco will probably be even less important in the tech world as time goes on. That said, San Francisco definitely has the largest tech industry, but that doesn't mean much for some people. For one, that means that competition for roles can be very intense. Also, tech is so large in SF that it's sometimes considered the only industry in SF, and as such it can be a little overbearing if you're trying to diversify your perspectives. Many cities in America have their own tech sector and you can usually slot right in if that's where your passion lies. It may not be as plentiful or as brand-name as SF, but you can definitely find something outside of there.
New York - Silicon Alley
Santa Monica - Silicon Beach
Kansas City - Silicon Prairie
Seattle - Haven't heard a name but I know they have tech jobs :)
Austin - Same as Seattle
Also many other places!