Put code /code blocks around it. It makes it much easier to read.

Your solution is to call an alias.

Code:
on @*:join:#dabigbadshow:{
  /notice $nick Please enter your age like this !18.
  /notice $nick You have 1 minute to do so $nick or you will be kicked.
  set $+(%,nick,$address) $nick
  $+(.timer,age,$nick) 1 60 checkkick $chan $nick
}
on $*:text:/^!(\d+)/S:#dabigbadshow: {
  tokenize 32 $strip($regml(1))
  if ($($+(%,nick,$address),2) == $nick) {
    if ($1 isnum 18-) {
      .mode $chan +v $nick
      $+(.timer,age,$nick) off
    }
    elseif $1 isnum {
      .mode $chan +b $wildsite $nick Come back when you are 18 or older.
      .kick $chan $nick Come Back After Your 18th Birthday.
      $+(.timer,age,$nick) off
    }
  }
}

alias -l checkkick {
  if $2 isreg $1 {
    kick $1 $2 Age required.
  }
}