That sounds tough Jake, it's very hard and disillusioning to be open with the people who are supposed to love and accept you only to be returned with mocking, judgment and insensitivity.
The hard reality is, you are a minor. You live in their house, and therefore you live by their rules. But don't worry, this too shall pass. When you're able to move out you can set up an altar, speak your meditations, and do your spells until your heart's content.
In the meantime, I would suggest that you put your focus and energy into other aspects of your life for the most part. I'm not saying don't continue to explore your beliefs, but don't allow it to become the only thing in your life.
There are some things you can still do to progress your beliefs until you're able to move out. First, Wicca and other paths require a good deal of reading and learning before you really have a good grasp on what you're doing and why. Use the time you have now wisely, because as you get older you may not have that kind of time available.
Meditation can be done silently (as already mentioned); or alternatively you can go outside to meditate and use vocals.
I wouldn't advise bringing any altar into your home that can be identified, even a small travel altar. The last thing you want to do is bring more upset to your family while they're adjusting to the idea of their child being Wiccan. The more respect you show them now, the more they are likely to show you in the future when they get used to the idea of your beliefs. You never know, maybe in a few months they'll start to rethink their current understanding.
However, if they're alright with you having crystals and candles you could start with those. Do some rock collecting, do some reading on crystal properties, look into some basic candle spells (those that don't include any excess tools-- or modify them to fit your needs). You don't necessarily need an altar to practice.
While I have a custom-built altar table, mostly I use it as a place to lay out divination spreads long-term so I can look at it more than once while processing the information. The rest of my workings are done outside, with minimal tools. Honestly, if I lost everything today, the only things I would probably replace are my Oracle deck, a few tea-light candles, an oil infuser, a quartz crystal, some stones I would find out on the street or park, and tea (because I always need tea...). Granted, I'm not Wiccan, but I rarely use anything else for anything I'm doing (and even then it's the use of things I can easily pick up from any craft store, like thread).
My long winded point: Use this time to do your reading, then decide what you will need long-term. Don't do it the other way around. You'll save a lot of time, money, and energy; and you won't step on any toes while doing it.