A D in a non-required course.

I would verify with CSULB admissions. Although you have met the CSU requirements, all CSU’s will provisionally admit you until final transcripts are sent. Did CSULB spell out your requirements to maintain your admission? Each CSU can determine their provisional admission requirements but the rule of thumb is to pass all a-g courses Senior year with a C- or higher. Nothing against your counselor but I would verify now so you will not get any surprises after your final transcript is reviewed when you may not have any options.

Good Luck.

https://web.csulb.edu/divisions/aa/catalog/current/admissions/provisional_admission.html