why I can not walk with the ship to the left with the arrow in my draft game?

I am new to “unity 3d”, can someone explain why I can not walk with the ship to the left with the arrow in my draft game?
Walk with all the arrows, but less with the left.
can someone help me?
I put the commands were these:

var vel = 50;

function Start () {
    
 
}

function Update () {
 

   if(transform.position.x<=-16){
    if(Input.GetKey(KeyCode.LeftArrow)){
      transform.Translate(vel*Time.deltaTime*-1,0,0);
}
}

  if(transform.position.x<=16){
   if(Input.GetKey(KeyCode.RightArrow)){
      transform.Translate(vel*Time.deltaTime,0,0);
}
}
{
     if(Input.GetKey("up")){
      transform.Translate(0,0,vel*Time.deltaTime*-1);
}
}
{
     if(Input.GetKey("down")){
      transform.Translate(0,0,vel*Time.deltaTime*1);
     
     }
    }
   }

Your if has a <= instead of >=. You need to change line 11 to:

if(transform.position.x>=-16){