I'm 23, would it be okay to take calcium, fish oil, multivitamin, and a baby aspirin daily for prevention and lower risks of any diseases?

Unlikely to: Cause any problems. Probably not necessary.

No data: No data has shown any of those will change the incidence of developing any disease in your age group (or for decades to come). You simply add cost and complicate your life. If you want to stay healthy, stay normal weight or reduce if over, eat a balanced, nutritious diet, don't smoke, and get daily exercise. Maintain positive mental health & keep busy. Wear your seatbelt and don't own a gun.