Um, forget all the advice above and do this one thing...DON'T.
You sound like a smart cookie getting all the pre-work done before bringing your snake home, but this is the one HUGE mistake you're making. Don't do this without the full support of your parents. If they bust you, you may have to rehome your snake and that's added stress to a little creature that doesn't need it. Plus your parents don't deserve to be lied to.
Be open with them, prove yourself as a responsible person excited to take this on, but if they say no respect their decision and get a snake when you're out on your own. They'll still be around.