I want to make the gameobject rigidbody.iskinematic=true for 3s and immune to damage when it triggers the collider and then false again

public class Personaje : MonoBehaviour {

 public float speed = 2;
 public int vidaMaxima;

 private int vidaActual;
 private Rigidbody rigidBody;
 // Use this for initialization
 void Start()
 {
     rigidBody = GetComponent<Rigidbody>();
     rigidBody.freezeRotation = true;

     vidaActual =  vidaMaxima;
 }
 
 // Update is called once per frame
 void Update () 
 {
     transform.position += Vector3.forward * speed * Time.deltaTime;
 }

 public void RestarVida()
 {
     vidaActual--;
 }

 public void OnTriggerEnter(Collider other)
 {
     if(other.tag == "Enemy")
     {
         //GetComponent<Rigidbody>().isKinematic = true;
         RestarVida();
         Debug.Log("Restar vida");
     }
 }

}