Witchipedia

My children were casting spells in elementary school. But they came from a family where such things were the norm. If your family is cool, then it's all good. But I am not a fan of kids doing things of which their parents don't approve. You can wait till 18 for that.

I'm a 16 year old neopagan witch who still hasn't told my mom about it, so I can relate to your situation. I don't think there's anything wrong with educating you self with the philosophies and information part of it before hand. But if you want to do a large spell or ritual you might want to inform them so they know what they're walking into if they see you burning stuff, mumbling things, or spreading out some spices from the kitchen all over the place.
That reminds me, if you want to wait to tell them, for whatever reason, then it would be impolite to borrow things like lighters, spices, craft supplies, etc.

I'm the same age, and I'm not a 'witch', yet. I really don't have enough access to supplies to initiate myself. I live in a small community, too, so I have no true access to covens. But what I do know is that being a witch is just like being Christian or Buddhist, or any religion. You're never too young to have your own opinions or beliefs. Logically, you're not to young to be a witch. However, you must know what you're getting yourself into when you're tampering with forces beyond yourself. Otherwise, of course you can be a witch! I hope this helps with your dilemma!