In this day and age I doubt they will care unless they are extremely religious, and have a problem with homosexuality. In fact it is really common for girls your age to have bisexual urges, and flip flop from being straight, gay bisexual, and then back again. It really isn't anything unusual. I have known several that made different announcements about their sexuality. These announcements are commonly only a big deal to the person giving them.
Most Helpful Girl
Personally, I would start to introduce it to them casually. A lot of older people don't even know what being pansexual means. They think people are either straight or gay, and that's it. So I would start to introduce them to the idea that sexuality is fluid. You can talk about it in terms of celebrities or whatever. That will make them more open to the idea of you being pansexual.
Go on with this sad face and just say (folks I went to the hospital today and I have cancer and I will day soon ) then when you see this shock and some cries you break out laughing saying (just kidding am just a panesexual nothing serious ) :D :D I think this will be a lot better for them now. seriously though I just wonder (I know it's non of my business but still out of curiosity) How do you know that you are pansexual?
lol you're 15 I hate when people decide so young shows how much decision making one has on themselves, but yea go date have fun which means you wanna FUCK I understand but take care of yourself and don't fuck too many people