This happened to me too...i am 14 and fixed this problem by myself a few months ago.
So first, you plug in the iPod and let it charge for about 10 mins or so...until it like starts to show the Apple logo repeatedly.
Then as its booting, HOLD DOWN the Home button, for approximately 10-20 seconds (sometimes you need to hold down Home and Power for 10 seconds, the the Home button for 10 seconds). Either way, you will get a PLUG INTO ITUNES screen, which is like an arrow pointing to the iTunes logo.
Then plug the iPOd into a computer with iTunes installed.
The computer itself will recognize an iPod (i did this on Windows)
and iTunes will display a msg that says "iTunes has detected an iPod in recovery mode blah blah blah." Continue iTunes' steps to reinstall the latest iOS and reupload/restore data onto the iPod...
As expected this will erase all previous data lol