I am actually pretty confused right now. I am 13 years old, and out to my friends as bi. I didn't actually find it any hard to come out to them, and I'm comfortable discussing it in public. I still find it hard to come out to my psychologist -so difficult actually, that I haven't been able to do it and don't think I can- or my family. My dad knows and is seemingly fine, but no one else of my family does. I find it very difficult to come out to adults. I'm afraid they'll say it's just a phase. Even if it turned out to be, it would hurt me that they wouldn't take me seriously.
I think at this point, most people have gotten over the idea that it's just a phase - there are millions of out LGBTQ people around the world; their existence can no longer be covered up or denied. However, you don't have to come out to anyone - it's all about what you're comfortable with. If you feel as if they'll take you more seriously when you're older, go ahead and wait. If you don't, just tell them when you're ready -if ever. Some people wait until they find a same-sex partner to take that step. Whatever happens, good luck!
