I don't think you can ever know with Fibro and that's a dangerous aspect of it. It's the sidekicks of Fibro that can be a problem, like costochondritis can mimic a heart attack, Interstitial Cystitis can mimic UTI, etc. The old symptoms of your Fibro, ex. muscle/ joint aches in the same places seem to intensify or last longer than when we were younger.
It's best to trust your own judgement and have a good primary physician who is willing to check out new symptoms and not brush it aside as just being your Fibro.

Years ago, I was told by a therapist that when I find my voice and speak of the tragedies in my life (openly mourning the circumstances I have survived) that the fatigue will leave my body. To a great extent that has happened, I don't suffer the intensity of pain like I use to in the beginning, Thank God

I think that's one reason why it can be important to get a diagnosis: because the diagnosis of fibromyalgia is one of exclusion. A doctor might exam you, order some labs, and then decide to refer you to a rheumatologist. They will order labs, imaging, take history, exam etc. If the rheumatologist rules out other conditions such as autoimmune diseases, osteoarthritis, and so on, that's important information. If everything comes back negative but based on the patient's history and exam fibromyalgia as a diagnosis makes sense, then the rheumatologist can go with that.
People can have chronic pain and fatigue for so many reasons. It's important to find out why.

That is such a good question, because I feel like maybe my aches are just age but the way they are so intense tells me it’s my chronic pain and fibromyalgia.

I believe because it starts when so young. I recd diagnosis in 30's but knew something wrong way before that. Arthritis normally shows when older