you're around my age then and IMO you'd probably enjoy the bar scene in the Old City area. If you wanted to check out the college age scene, in a packed place, wait forever for drinks, etc., then Cool Beans is probably your best bet (off the strip).
just tell em to take you to old city, you'll be able to walk around and look into to each bar and see what's what, there's quite a few all centrally located. It's not a very big area.