The laws that apply are the state in which you are sued (Colorado). Colorado does have a "borrowing statute" that says if the cause of action arises from a state with a shorter statute of limitations that state's limitations apply. So the next question is where did the cause of actoin arise from? Just because you "opened" an account somewhere doesn't give you safe harbor by that rules. It's likely if you used the card at all after you moved to Colorado then they probably can argue that the event took place in Colorado. Even if all the charges took place in California, if you left the state before the limitations ran out, the limitations period there is TOLLED (i.e. put on hold).
As you probably know, credit card debts statute of limitations is six years in Colorado and 4 years in California.