The more you build it up to a momentous, life changing occasion, the more likely you let yourself down with a failed resolution later. You can start making a positive change in your life any day of the year. No need to wait for tomorrow if today will do.
And speaking of resolutions: skip them. Focus on building the right habits instead. If you don’t know where to begin, read Atomic Habits. Easily the most valuable book I read all year.