SF - Interview Scheduled, Can see Interview Letter Online, but no Mail received

[etoile0804]

Hello,

My interview is scheduled for this Friday, Dec 21 @ 9:25 AM.
I can see the interview appointment letter online on USCIS website but until today I have not received the actual appointment letter in the mail yet.

I just printed the appointment letter out using my printer and I am going to bring it with me this Friday.
Would this cause any problems? Did anyone have the same experience before?

Thanks!