Grinding will eventually destroy teeth. I have ground my teeth since I was a kid. I was first treated for TMJ by a military dentist. Got my first night guard and actually had to wear a plastic splint during the day too. But it did resolve some of the pain issues. And the headaches which were constant by that point.
After leaving the service, I stopped wearing my night guard. Within a few years my molars were breaking. For no reason, chunks of them would just break off. The years of grinding had fractured them. I had extensive treatment for TMJ that included reconstructive surgery and realignment of the teeth (braces). Took years, tons of money, and tons of pain. And I still grind my teeth! I am currently using a nightguard that was made by the dentist. It was pretty expensive but seems to work.
If my DD were grinding, I would have her at the dentist to talk about it very quickly. Perhaps some intervention now could save her a lot of grief later on. At least getting used to the night guard concept young would have her in the habit before she did permanent damage to her teeth. If I had all the money I've spent trying to save my teeth, I could probably pay for her college without borrowing!