My flight is on January 16th of next year (from PEK to LAX).

but my room-and-board situation only allows me to stay there until January 15th so I'm planning on staying at the airport. If I'm this early, does this mean I'll have to wait outside the actual terminal because I can't check in yet? Also, if that's the case, am I allowed to stay in the inside of the airport overnight? Just making sure... thank you!