I can definitely understand your fear, as it's something I've been going through for some time as well. But let me share a few thoughts. First off, while it's possible to get this at a young age, the stats are heavily in your favor. I was actually just reading it a couple of weeks back. A 30 year old male has something like a .06% chance of developing it over the next 10 years. And you're not even 30 and you're female, so that number is going to be lower. Also remember that many of those who are young and get it have some background - family history of getting it young, for example. So you're putting yourself into a very small camp indeed. Thirdly, remember that most of those who get it have a variety of big symptoms. My Aunt had it in her 50s, and while I don't know all of her symptoms, I do know she had extreme weight loss with no explanation, which is something I've heard in many cases. I can totally understand your worry as I've been there and am there sometimes still, but statistically you're in a good position.
Secondly, let me encourage you to try your best to control your imagination. I have a pretty vivid imagination so I've been there! I think about what's going on, and think of going to the doc and getting the test results with the doc telling me "you have cancer" and emotionally it really spirals out of control. But that's purely imagination. And I've had it so many times with so many issues. Why not try letting your imagination take you in a good direction? Imagine going to the doc and him saying "everything's good!" with a smile. As I mentioned before, this is far more likely on a statistical level anyway. But I think it may be one of the best ways to combat the negative imagination us hypos have.
Either way, good luck with it all - looking forward to hearing the test come back with good results for you :)