Player Inconsistent Jumps

Hey, when my player jumps, it's not always the same height. I can be 2 inches sometimes 10 feet. So, here's the script!

     public float jSpeed = 5.0f;
     public float gravity = 9.8f;
 
     private CharacterController cc;
     private Vector3 move = new Vector3(0, 0, 0);
 
     void Start() {
         if (GetComponent<CharacterController>())
             cc = GetComponent<CharacterController>();
     }
 
     void Update() {
         float jumpInput = Input.GetAxis("Jump");
 
          //GRAVITY
          move -= new Vector3(0, gravity * Time.deltaTime, 0);

         // JUMP
         if (cc.isGrounded){
             move += new Vector3(0, jumpInput * jSpeed, 0);
         }
 
         cc.Move(transform.TransformDirection(move * Time.deltaTime));
 
     }