I am not a LEO, judge, or lawyer.
Premeditation in this case would only apply to states that prohibit the carrying of a knife for SD whether it be lawful or unlawful. Many more states make it perfectly legal to carry a knife for lawful SD. Premeditation, if proven, might lead to a misdemeanor weapons possession charge in one of the former states. When it comes to justification for actual use of deadly force, the circumstances are supposed to be looked at independent of the tool used. Any charges related to lawfully defending yourself with an "illegal" weapon are a separate issue. There's a lot of precedent at the appellate level establishing this principle. Not that a prosecutor won't make the attempt, but if your judge isn't biased and your lawyer is any good, that sort of tack won't go far in court.