Why can't I add a light to a script?

I’m new to C# and I’m not very good at it, I’m currently trying to make a light that brightens up, here’s the code
using UnityEngine;
using System.Collections;

public class LightTestScript : MonoBehaviour {
    public Light LightPoint;

    // Use this for initialization
    void Start () {

	// Update is called once per frame
	void Update () {
        LightPoint.intensity = Mathf.Lerp(LightPoint.intensity, 100f, Time.deltaTime);

I don’t know if anything is wrong with it, I’ve tried dragging and dropping the light into the Light section but to no avail.

Light intensity only goes up to 8 anyway so 100 will instantly increase it to max. Also your doing = each time not +=. Really though just try something far more simple like this…

LightPoint.intensity += 0.3f * Time.deltaTime;

EDIT - By the way your script works, the only thing I changed to get it working in a noticeable way was delete the directional light from the test scene I created and that one line. Dragged the script on the point light and the point light onto the public slot in the inspector, worked first time.