title: How to construct a regex expression for username validation?
body: <p>I'm working on constructing a PHP regex expression for a username validation that has the following constraints:</p>
  
  <blockquote>
    <p>-must be 10-16 characters long, with a combo of alphabetic, numeric, and atleast one special character (*&amp;^-_$)
    -can't start with a numeric or special character</p>
  </blockquote>
  
  <p>CORRECTION: the last SIX digits must be a month/date birthday (<code>MMYYYY format</code>). In order to further validate the username, the month/date must show the username is over 18 - if not, the username will not validate. Thank you in advance for any assistance! I've been stuck on this for a while.</p>