this is sooooo important in your faith walk. It's also, admittedly very hard but every person claiming to be a Christian should repent. There is a huge difference in admitting one's sin and truly repenting of one's sin.
True repentance isn't saying sorry. It means to stop going your direction and start going God's direction. True repentance is giving God everything - the good, the bad, and the ugly. It's complete and total surrender. Thank God for repentance.