About your age

<html>
<head>
<title>cal</title>
</head>
<body>
    <form>
    how old are you: <input type="number" name="age" />
    <input type="submit" value="Enter" />
</form>
  <?PHP
    $age=$_GET['age'];
    $correct=false;
    if ($age) {
        echo "you are $age years old <br />";
        if (($age>=0) && ($age<13)) {
          echo "si dieta";
          $correct=true;
        }
        if (($age>="13") && ($age<18)) {
          echo "si teenager";
          $correct=true;
        }

        if (($age>=18) && ($age<65)) {
          echo "si dospeli";
          $correct=true;
        }

        if (($age>=65) && ($age<120)) {
          echo "si stary a na dochodku";
          $correct=true;
        }

        if (($age>="120") && ($age<99999999999999999999999999999999999)) {
          echo "si davno mrtvy";
          $correct=true;
        }
   }

   if ($correct==false) {
    echo "dal si zle cislo alebo si vymyslas";
   }

  ?>
</body>
</html>