I'm 30/f and my partner is 42/m. if i get pregnant this year what is risk of autism or schizophrenia due to age? anything i can do to minimize risk?

Same as anyone: Neither of you are at increased risk of anomalies due to age. It depends on your family (and his) history. We don't know exactly what causes schizophrenia/autism but know it is multiple factors. Live healthy and take Folic Acid to prevent neural tube defects. Get your (and his) vaccinations up to date. Vaccinations do not cause autism!

Risk: None of those disorders have any age related risk. If you plan to get pregnant, make sure you start taking prenatal vitamins preferably a few months prior to conception.

Risk of mental probl: Minimal risk if no one in generations above you and among your siblings have no alcoholism, drug abuse, or severe mental problems.

I think your fears: Are based on older research. When very few people were having children later in life the statistics were skewed. Since this has changed i believe the risks of retardation and mental health problems are no longer showing as higher for older couples. Eat healthy foods, exercise. Relax and get good prenatal care. Enjoy your pregnancy and the beginning of becoming a parent!