I know, it stinks. You finally sat down and had The Big Talk with your parents and they still won't let you practice Wicca in their house. It's not fair, you might just hate them for a few minutes, and they're the meanest parents ever. Take heart - there's a positive side to this. If you can't practice Wicca while you live under their roof, that means you'll have all kinds of free time to do other stuff. And that other stuff can be just as educational to a future Pagan or Wiccan hopeful.
Yes, I'm serious. Plants. Pick up a book on your local floral and fauna, spend time in the woods, grow a selection of herbs, or a flower or vegetable garden. Take a class on horticulture at your local college extension, if it's available. Volunteer at a local metro park or nature center. Study up on the Doctrine of Signatures so that by the time you're out on your own, you'll know exactly why herbs work the way they do.
Sure, they make you take an entire year to learn about a bunch of dead white guys, but there's more to history than that. If you are interested in Roman gods, for example, pick up the writings of Julius Caesar or Ptolemy. If Celtic history is more your flavor, grab a copy of Ronald Hutton's The Druids or Peter Beresford Ellis' books on the Celts. Choose the history you want to learn about, and learn it. Later on, when you begin practicing, you'll understand rituals a lot better if you can imagine them in a historical context.
If you can learn to follow a recipe, you can learn to follow spell and ritual instructions. Not only that, Pagans will have a potluck at the drop of a hat, and you don't want to be showing up with a box of Chips Ahoy when your coven sisters have all spent hours making casseroles, trust me. If you don't know your way around your home's kitchen, now's the time to learn. Ask a parent or older sib to teach you -- they'll be impressed that you're taking some initiative, and it will give you some family bonding time. If no one's available to teach you, get a cookbook -- there are hundreds aimed at the beginning cook. Figure out a couple of dishes you're good at, and practice them until you're amazing.
Some high schools require their students to do a certain amount of community service, and if you go to one of them, then you're a step ahead. Be assured that most covens expect their members to be useful members of the community as well. Spend a few hours each week volunteering at your local library shelving books, or at the animal shelter scooping up. The adults will be impressed with your good attitude, and you'll gain something from the experience as well -- the ability to do things for others with no expectation of payment.
Okay, I know it sounds silly, why would you want to study Christianity/Judaism/Islam/Scientology/Whatever as a precursor to studying Wicca? Well, because believe it or not, a lot of times there's a lot more there than you've really paid attention to. If you've grown up in a certain faith, you probably take it for granted. Stop doing that, and take some time to really ask questions. Go in depth, and figure out what it is you disagree with or agree with. You may find that the religion you've been brought up in isn't so bad after all, even if it's not the right one for you, and you'll certainly gain a better understanding of where your mom and dad are coming from. Learn about other religions too.
Seriously -- if your city has a planetarium nearby, go there. For the ancients, so much of what they knew was determined by tracking the movement of the stars in the heavens. Learn about the constellations, the movement of the planets, all the things that go on thousands of light years away. It will come in useful later on, particularly if you develop an interest in astrology.
Part of a well-balanced life includes taking care of yourself not only spiritually but physically. Exercise, even if it's just going for a walk on your lunch period at school. Take a yoga class, or meditate daily. Eat a balanced diet -- a lot of high school kids have to eat lunch at 9:30 in the morning due to overcrowding issues, so make sure that around noon you have a healthy snack, like an apple or a granola bar. Add whole grains into your diet, cut back on sugars and empty calories. You can tie this into your new cooking lessons too -- learn to prepare healthy meals for your entire family.
Think you might be interested in Norse religion because your family's Scandinavian? Great -- start learning about your ancestors. Figure out who they were, where they came from, what they did, etc. There are a ton of great genealogy resources on the web to get you started, and this is a project you can share with your whole family. It's inherently satisfying to look at a huge list of names (I have over 9,000 people in my own database) and say, "I share blood with these people."
Nearly all Pagans and Wiccans regard our planet as sacred, so quit throwing your Cheetos wrappers on the ground! Take some time to learn about things you can do to help save the planet. Begin a recycling program at your school if you don't have one. Organize a newspaper collection drive and donate the money to an earth-friendly organization. Or just start small, by getting some trash bags and cleaning up your own street (many areas have a Keep Our City Beautiful plan where they'll actually give volunteers bags and gloves to do a cleanup). The earth is our mother, so learn to treat her with respect.
When you get old enough to join a coven, if that's what you want to do, one question that may be asked of you is, "What can you do for us?" This is where having a skill comes in really handy. If you can say, "Well, I sew so I could help people make ritual robes, and I taught myself metalworking so I'm good at making jewelry, oh, and I've just taken up candle making ", then you are a well-rounded person indeed. You are someone who will be worthy of consideration. Learn to do something with your hands -- it not only occupies the body, but the mind as well. Find something you love, and practice it until you've turned it into something beautiful.