DateTime.Now gets reset at runtime

Why Does this variable loose it's value and how do I stop it?

 using System;
 public class Whatever : MonoBehavior{
 DateTime awakeTime;
 Awake(){
     DateTime awakeTime = DateTime.Now;
     Debug.Log(awakeTime); //returns 10/13/2018 12:49:24 PM 
 }
   void OnGUI(){
     if(GUI.Button(new Rect(10,180,100,30),"readTime")){
       Debug.Log(awakeTime);  //returns 01/01/0001 12:49:24 PM 
     }
 }