I have Elements 12 and I have updated it. When I try to use the pen, the pen shape is not on the screen. It is as though it is invisible. The pen information is at the bottom of the screen.
What is your "Elements 12" - Premiere Elements 12 or Photoshop Elements 12?
If your program is Photoshop Elements 12, you have posted in the wrong forum. Your thread has been posted in the Adobe Premiere Elements Forum (video editing).
If the issue is with Photoshop Elements 12, please re-post your question in the Adobe Photoshop Elements Forum or wait for a moderator here to see your thread here and move it from here to there.
Add On...If you are in Photoshop Elements 12 as I suspect, are you in the Expert or Quick workspace and what and where is this "pen" shape to which you refer?