What is the safest age for a woman to be when she gives birth? I heard over 30 is "borderline" and over 35 is potentially dangerous! Any insights?

Mom's age. It is not the mother's age that's important , but the state of her health as long as the baby has normal chromosomes! every child deserves to be plannned and wanted and born to parents who are ready to be parents.
Younger is better. Some rare genetic conditions occur more often as a women gets older. The risk goes up gradually each year from 18 yrs old on. For avoiding rare genetic disorders younger is better. Risk of blood pressure and diabetes problems also goes up gradually with age for those who are already at risk. The statistical difference between 30 year old risk and 35 year old risk is small for most conditions.