Mine

alias alter {

  var %day = 24
  var %month = july
  var %year = 1994
  var %hour = 04
  var %minute = 0
  var %second = 0

  var %seconds = $calc($ctime - $ctime(%month %day %year %hour $+ : $+ %minute $+ : $+ %second))
  var %bdthis = $calc($ctime(%month %day $asctime(yyyy) %hour $+ : $+ %minute $+ : $+ %second) - $ctime)
  var %bdnext = $calc($ctime(%month %day $calc($asctime(yyyy) + 1) %hour $+ : $+ %minute $+ : $+ %second) - $ctime)
  var %seconds2birthday = $iif(%bdthis > 0,%bdthis,%bdnext)
  var %days2birthday = $calc(%seconds2birthday / 3600 / 24)
  me is $calc(%seconds / 365.25 / 24 / 3600) years old ( $+ %seconds seconds) - Next birthday: $round(%days2birthday,0)  $iif($round(%days2birthday,0) == 1,day,days) left
}