(NSFW) Did I wait too long to take plan B?

So pretty much my fiance and I “did it”. But we waited until three days later to take Plan B. And I do know that it is not to be used as a form of birth control. And The reason we were not able to get it sooner was because we were very busy. Even though I started my period from the Plan B….is there still a chance we waited to long? And if so would the baby be safe??