Bisexuality Support Group
Bisexuality is a sexual orientation which refers to the aesthetic, romantic, and/or sexual attraction of individuals to other individuals of both their own and the opposite gender or sex. Most bisexuals are not equally attracted to men and women, and may even shift between states of finding either sex exclusively attractive over the course of time.
Hang in there, the right time will come for you as well.
I'm also pansexual, though I generally call myself bi out of simplicity. I completely understand your fear. I recently came out to my Mom and my 2 kids (14 and 9) as bi and poly. It's always scary coming out, regardless of specifics. People never seem to respond how you expect them to. I did it because I found 2 amazing women and hiding my feelings was making me miserable. So far reactions have been ok. But I didn't have somebody specifically homophobic.
Your concern about your relationship with your dad is very valid. This isn't something you have to rush into saying. Take your time to feel confident and strong in your sexual identity. Build a community support network to support you when you do come out. (Check out your local LGBTQ center.) Work on exposing him to LGBTQ through friends, discussions, etc. Discuss news when it involves LGBTQ.
You can wait to come out at least until you have a woman in your life (or other non-cis-male since you're pan!). One thing my girlfriends told me when I came out - Do not treat this as something you have to apologize for, defend, or explain. If you make it a big deal, it'll be a big deal.
Good luck!! I know this is hard, but it's wonderful that you're embracing your sexual identity so young. I can't promise everything will go smoothly and you'll be accepted for who you are. But I CAN promise you will be happier for being true to yourself.