i cant find my i tuens library

The usual location for your iTunes library data on your Mac is

[startup disk]/Users/[user account home folder]/Music/iTunes/

Startup disk is usually called Macintosh HD, unless you changed it. Unless you changed it, the iTunes folder contains your iTunes Library.itl file (which is your "library" database) and the iTunes Media folder (which contains your iTunes media files).

If that does not help, or you mean something else by can't find iTunes library, please post back with more details about your situation.