How old do yu have to be to buy a Dildo @Spencers?

It's my Stepmothers bachelorette party &i wanted to 'surprise' her, mostly missing with her. But idk how old yu have to be, I don't wanna walk in there buying a Dildo &the cashier looking @me lik ummm yu have to be 18yrs or older. How Embarrising tht would be!