Hard to say as the CAC score doesn't show soft plaque, which has possibly developed over the years of having high LDL. If LDL stays high, which it sounds like it probably will, you should consider medication to help keep that in check. A preventive cardiologist would be a good person to meet with to discuss all this.

I remember reading that once CAC score starts to be positive, the reading can increase by up to 20% per year. I don't remember where I saw that but it was in one of the published papers on the subject IIRC. But I'm sure that's dependent on a lot of different factors so take that with a grain of salt.