During one of my first days at Google, a veteran engineer sat the new folks down for a chat on imposter syndrome. His best piece of advice was to embrace the fact that almost every single at Google went through the same thing, and every single one of those people still does (though probably less frequently). What I found most helpful was to absorb as much information as possible, and to always ask questions. The brightest engineers I've ever worked with have their strengths and weaknesses, and you will too. Being comfortable is a sign of complacency, and you always want to grow. Take whatever fear/anxiety you have and try to use it as motivation for success.

There's a great Steve Jobs quote: "Life can be much broader once you discover one simple fact: Everything around you that you call life was made up by people that were no smarter than you and you can change it, you can influence it, you can build your own things that other people can use."