Welcome to the forum, Snowboarder.
The first thing you need to do is get yourself a private email address like https://mail.google.com/ so that you can contact your 'worldly' family without worrying about your parents looking over your shoulder.
When you are on your home computer, use Ctrl+H to delete your history, or set the browser to delete it when it closes. Never let it remember passwords.
You don't have to tell your parents, or any other JW anything. It is especially unwise to tell them their religion, or even a doctrine, is a load of crap. Get into the habit of not answering their questions. They say they have the Truth, so their only job is to answer yours.
If you don't want to pioneer, just stop. If they want to know why, just tell them you don't want to, you are too busy, you want to go snowboarding, you need an education. Open the WTCD, type in 'within our twentieth century', select the book, 'Know Jehovah' and ask them to read paragraph 9 (page 216) to you and explain it to you. Ask them if Armageddon comes as soon as the WT pretends it does? Ask them why this paragraph should give you any confidence that it would be ok not to get a good education in the twentyfirst century?
If they still don't want you to get an education, ask them how far into the future does the new overlapping generation doctrine push Armageddon? Ask them to use a calculator to work out how long it might be. Ask them how they think you are going to feel if you ignore the fact that the WT has failed to deliver in the past and end up trying to support your future family on window washer wages? Ask them to explain the new generation doctrine to you using dictionaries and Bibles, and don't let them get away with anything. Ask them how they will feel in 40 or 50 years time if the WT changes the generation doctrine to two overlapping lots of contempories, or something equally unbelievable, and you are still washing windows and pioneering? If they say anything that is stupid, or that they can't prove, don't tell them why they are being idiots, just ask them for proof until they admit it.
If they try to bully you into believing something without proof, compare it to a Catholic believing the Pope without doing the research to check out if what he said was correct. Act offended that they should treat their own son in such a way. Make them feel guilty.
We didn't ask our parents to raise us in this religion. That was their choice. They joined a religion that requires its members to treat its exiting children badly. They didn't have to encourage you to get baptised. That was a risk they took. They have to decide what price they are going to pay when their children leave the religion. They didn't stick with the religion of their birth. All we want is the same freedom to choose religion that they demanded. Point out any double standards they try to use on you and make them feel guilty for it.
Remember, you don't have to tell them anything. Most of the time, keeping your mouth shut is the best option, but when it isn't an option, just keep asking questions in such a way that they feel obligated to answer them, and then make them feel guilty if they use any tricks to weasel their way out of it.
Stick around and ask as many questions as you need.
I passed my suitcase out of my window, had breakfast, said goodbye to the dog and disappeared. I was 17. I don't recommend that. In hindsight, I should have stuck around until Dad admitted he didn't have sensible answers to my questions. 50 years later the relationship is still dysfunctional and he has been a member of the cult for so long that regaining his sanity is not an option.
Cheers
Chris