BAB

<form action="" method="get"> <!-- Please use Post instead of Get -->
  <table class="table table-normal">
    <tr>
      <td>Name:</td>
      <td>Age:</td>
    </tr>
    <tr>
      <td><input type="text" name="name" placeholder="Enter your name"></td>
      <td><input type="num" name="age" placeholder="Enter your age"></td>
    </tr>
  </table>
  <input type="submit" name="submit" class="btn btn-lg btn-primary" value="ENTER">
</form>
<?php
  $name = @$_GET['name']; // or use POST
  $age = @$_GET['age']; // or use POST
  if(isset($_GET['submit'])){
    if(!empty($name) && !empty($name)){
      echo "<p class='success'>You are " . $name . ", and you are " . $age . " Years old</p>";
    } else {
      echo "<p class='error'>You must enter all fields</p>";
    }
  }
  // POST method is much better then GET
  // It doesnt look so creepy <img src="https://phpacademy.org/img/smileys/wink.png" width="18" height="18" alt=";)" title=";)" class="bbcode_smiley"/>
  // But Get looks awesome with .htaccess - RewriteRule
?>