My ipad2 screen is off-centered, is it normal?

Not Really.

Try rebooting your iPad. Press and hold BOTH the home and power buttons at the SAME time for about 10 seconds (ignore the red slider to shut down) until the Apple Logo appears, then let go of both buttons and your iPad will restart. You will not lose any data or settings. See if the screen is normally positioned once it comes back up.

It's possible you have Zoom on. Go to Settings > General > Accessibility and see if Zoom is on. If it is, turn it off.

If you have an Apple Store near you, make an appointment at the Genius Bar.