She had seen a lot of things. Mary had a unique perspective on the entire situation with the birth of Christ. Read Luke 2:19.
But Mary treasured all these things, pondering them in her heart.
Luke 2:19 NASB
Her perspective was unique, but it was a treasure to her. She valued and prized those memories and all that went with them. When we think back to our experience with Christ, do we treasure our interactions with Him? Do we meditate on those interactions?
Mary saw all that Christ was doing in bringing people to him and she took time to think about and to values those interactions. Do we value the same things?