G, Please don't panic. If you get it, you get it. Like many other things. Ex: you can't get married panicked you're going to divorce just because it's around or in your family. That's no way to live, am I right? There are many ways to cope and mitigate your symptoms. Ironically, with your mom having it, you have a leg up in identifying whether or not you have it. The earlier it's properly ID'd and then treatments and behaviors put in place, the better chance yu have of reducing its severity. Stress, even anxiety based stress, is not good for you.
Now, to directly respond to genetic ties in Fibromyalgia. Almost all research I've seen claims there is a genetic predisposition to it. Generally, no one knows what genes you end up with, i.e. there's no known test or marker for it. Even diagnosing is by clinical observation and elimination of other causes of one's symptoms; no conclusive 'test' is available to be certain that is one's affliction.
I understand the theory is that while there is a predisposition, there is nothing clear that if you have the genes you'll get it or that if you don't have the genes you won't get it. Still a crap shoot.
In my family, we have identified four generations. While no one knew what it was fifty years ago, as women were thought to be hysterical and weak, I know my grandmother had it. My dad had a lesser version. I and my only two siblings have some variety and my youngest daughter have it. So, we all had/have the predisposition from genes.
Keep in mind, the theory, as I understand it, is that there must still be a triggering event: either a significant physical stressor (like whiplash from car wreck or dealing with a potent virus like Epstein-Barr) or an emotional stressor (like divorce or a death accompanied by perhaps long-term mourning).
We can't avoid genetics after we were born--yet. And, truthfully, we can't avoid potential harsh stressors all together, either. But we can be informed, reasonably vigilant and educated and if it should be your turn, you are ahead of the game to be proactive early. I wish I had had those advantages. And, I'm sure many, many others would feel they would have had an easier time if they knew what it was and what to do about it early on. And, too, due to genetics, you may be ahead because very often what worked for your mum will help you, too. Shortens the guessing game for your particular treatment.
I have a tendency to be fairly straight-forward. I hope my information is correct. I try to be. I hope this frankness provides you some relief from your dread & anxiety over anticipating Fibro. It's an adjustment-sometimes huge. But you CAN navigate the journey.
I believe FM to be a trauma-based syndrome and as such would have to go through some sort of emotional, mental, or physical event that would trigger FM symptoms to come on. Hope this helps!! *hugs*