J.N.D. Kelly gives 2 Peter a relatively late date (between 100-110 C.E.). The Anchor Bible Commentary provides this information: "many scholars have assigned Second Peter to a date as late as around A.D. 150. This has been done on insufficient grounds. References to Gnosticism and other movements are not conclusive, as these were already present in the first century . . . The present writer is inclined to date Second Peter about A.D. 90" (Bo Reicke, 144-145).
Norman Hillyer (New International Biblical Commentary) concludes that "2 Peter itself must have been widely accepted as authentic at an early date [in the first century], despite any later uncertainties that crept in" (Hillyer, 12). He puts paid to the notion that Peter copied from Jude. So does Bo Reicke.
I plan to wrote more on this subject.