Depending on the level of pedantry you want you could argue for either. Washington's measure went into effect first, on Dec 1st, 2013 while Colorado's went into effect on Jan 1st, 2014. Colorado opened retail shops that same day though while the first shops didn't open until July 2014 in Washington and they had a lot of initial issues around licensing leading to slower expansion.

Sure, but in reference to the comment "because of the time difference" it seems pretty obvious he was referring to time zones, not the dates the laws took effect.

Anyway, it doesn't actually matter. Cheers.