No, for two reasons. One, while some retailers might decide that "scissors" are really knives and so they'd best act as though you're buying a knife that is not the law. So, this is not something you "have to" do, it's a store policy, like if they won't sell you more than six rolls of toilet paper at a time.

Two, if you're old (which unfortunately I am) then your apparent age is enough anyway. I do not ordinarily carry ID. Nobody stops me buying alcohol, entering nightclubs, watching movies, or doing other age-restricted activities, because "This person is obviously like, fifty?" is enough.