I was in a similar situation as a high school senior. I had found out about 2 years before that my dad was an alcoholic and I was conflicted. I hated him for doing the things he did and seemingly causing my "perfect family" to fall apart. On the other hand, I was daddy's little girl and I wanted nothing more than to hug him and never let go. After all, he was my dad.
I'm 24 now and have been through quite a bit with my dad. I can't even begin to think about forgiveness. Things are still too raw and I've been out of the house for 6 years now. I know that forgiveness is for me, but I'm still angry and hurt.
I guess my point is please don't rush it. Forgiveness, in my opinion, is a huge deal. As you may know, there's no timeline for this stuff. It will be with you the rest of your life. Do it on your own time and in your own way. If now is good for you- then by all means, but know that no one here is going to blame you for not forgiving him right now.
Thanks for letting me share.