Is it certain that my hearing loss will get progressively worse until I can't hear anymore? Or is there a chance that this is the worst of it and my ears will age at a normal pace now?

There's definitely a chance, hearing loss can come as a result of any number of conditions and not all are progressive. Some just happen one day, either as a result of individual biology or an accident. I personally am experiencing fluctuations in my hearing alongside other issues, and we don't know yet whether that will translate to a permanent and/or progressive loss.

If you haven't had the cause of your loss diagnosed, that would probably be the next step since a hearing loss at your age indicates something is going on with your health. An ENT is who you'd want to look for.