It isn't because you're aging that you can't remember birthdays! Depending on your smart phone to remember phone numbers, GPS to remember how to get from Point A to Point B, and the Cloud for everything else just makes your brain lazy!
Flex those mnemonic muscles!
Squish a stress ball. Subjects in tests did better at recalling lists of words when they squeezed a stress ball in their right hand while memorizing and in the left while recalling.
Eat more omega-3s. The fatty acids may improve short-term memory.
Exercise. Studies show that breaking a sweat increases hippocampus volume in all stages of life.
Drink coffee. Caffeine may aid a hormone that helps the brain consolidate information.