I actually did some casual research into this 3 years ago before my kids were born. All the theories and speculation in the article have been disproven - specifically theories about autobiographical memory or narrative memory being important. What actually happens is the brain undergoes periods of shift/growth/change that nuke the ability to recall earlier memories. Most of the incorrect explanations come from adult-oriented bias: The memories are so far gone we can't even remember that we were once capable of remembering earlier times.
Children can remember events clearly from before they acquired language. No adult has ever been shown to have this ability (it is always due to mis-remembering the time period or making educated guesses based on other knowledge). As children get older and gain a better mastery of language they can often describe _more_ memories from very early childhood, indicating that the memories exist even when kids lack the ability to describe them in words. These abilities to remember early childhood (even <1 yr old) begins fading around ~10 yrs old. By your teenage years those early memories are mostly gone.
Where have you read about the very early memories, like <1 year? There is a thing that puzzles me most of my life. When I was a teenager we had a family discussion about early memories. I have described several ones I've always assumed to be my earliest, but I've never knew what age they are related to. In one of them my cradle was involved and I was told by my mom that I was removed out of cradle at the age of 3 months.
Children can remember events clearly from before they acquired language. No adult has ever been shown to have this ability (it is always due to mis-remembering the time period or making educated guesses based on other knowledge). As children get older and gain a better mastery of language they can often describe _more_ memories from very early childhood, indicating that the memories exist even when kids lack the ability to describe them in words. These abilities to remember early childhood (even <1 yr old) begins fading around ~10 yrs old. By your teenage years those early memories are mostly gone.