Get a test kit. They come in discreet packaging, so as long as your parents don't open your mail, there shouldn't be a problem. If they do go through your mail, just take the effort to walk to your mailbox to grab the mail until the kit arrives. It's an important investment if you roll a lot, or if you roll at all for that matter.
Also, if you've only rolled at raves/events I'd definitely suggest rolling at hoe with a few friends, a significant other, or even by yourself. It's an entirely different experience that I believe everyone who uses MDMA should try at least once. Going to park and non MDMA related events can also be really fun.
Similar to the above suggestion, but if you've only rolled at home, try it a club/rave/show. It's really fun for a lot of people, just remember to be safe because it can be a little overwhelming.
Another thing I'd like to point out to you is the "E-Tard's Bible" It's full of a bunch of fun things to do while rolling, but it also has some weird/crazy stuff in there, so you might not want to do it all

Here's a link:
http://www.bluelight.ru/vb/showthread.php?t=230119
Since you've read the "everything you need to know about ecstasy" thing, I'll spare you all the safety precautions that you've probably read a billion times, and just give the highlights. Drink water, but not too much (google 'MDMA related hyponatremia' if you want to know about how you can drink too much water) keep something to chew on (binky, gum, whatever works for you) and just stay generally safe and have fun.
Hope you have a good time rolling :D