Forgivness ceremony

The Cherokee tribe that lives near me has invited me to a forgivness ceremony. I think it sounds like a beautiful ceremony. My problem is I have a really hard time forgiving people. I have grudges going back over 20 years. How does one forgive? I know I should be able to. Im considering not going to the ceremony, because I would feel hypocritical. Maybe I can learn to forgive. Anybody have Ideas?

Mekka