Problems with Initial Velocity

I just download Unity the other day, and I was messing around with it. I found a really cool online tutorial about how to make a quick little 2D pong game. I figured that it would be a good way to get used to some of the basics of working in Unity. I have no prior programming experience so everything is fairly new.

Each of my paddles/rackets works fine independently, but the ball itself won't start moving right away. At first, I manually typed in the entire script, but when that wasn't working I just copy pasted the creator's script to see if that worked, and for me, it hasn't.

public class Ball : MonoBehaviour { public float speed = 20;

 void start() {
     //Initial Velocity
     GetComponent<Rigidbody2D>().velocity = Vector2.right * speed;
 }

are there any ideas as to why I might be having trouble?