Mri of brain revealed mild cortical atrophic changes. i understand age can be a reason, but i'm 41. my memory isn't great. what does this mean?

Abnormal MRI: It is unusual for a young woman to have atrophic changes on a brain mri. I see you have had more than one episode of head trauma, so it would be a good idea to have a neurologist look at the MRI and evaluate you in person. There are other studies that can be done to assess for a brain problem, including eeg, spinal fluid analysis, pet scan, and blood tests.

It would be quite unusual for brain atrophy to be due to "aging" at 41 yrs of age. This could be a sign of early dementia, and needs a thorough evaluation, especially in view of memory problems. Many reversible disorders could be potential culprits. See a neurologist and get this addressed.