Night vision only gets worse with age in the same way that vision tends to generally and naturally worsen for everyone as they age. Worsening night vision is generally a signal that overall vision may be worsening, not necessarily a sign that only night vision is getting worse.
It’s advisable that you discuss concerns like this with your ophthalmologist if you are concerned about worsening vision, whether it is in all driving scenarios or limited to nighttime driving. Your doctor may be able to pinpoint a developing eye-related change and make suggestions to help you strengthen your eyes or get a prescription to help with a developing, but manageable vision problem.