My oldest memory is a clown holding a bunch of balloons flying over the fence at my first birthday party. I then tried to fly with the baloons when i got them.

I told my mom about it decades ago, and she said there was a clown that jumped over the fence. Then I spent the rest of the party running around the house holding the balloons.

Similar situation. I have no doubt that a large fraction of my childhood memories are fabricated, but there were a few that I kept to myself until I was over the age of 30 and were later confirmed by a parent or aunt or uncle.

There's also the phenomenon of having a memory of a memory. At age 10, I had a very solid recollection of my life at ages 5 to 6 (not so much of age 4). Now all I remember is that I used to remember a lot more than I do know.

Yea, I have a couple of early memories that I can date from ~1-2 years old (early bday party, birth of sibling). And presumably a few more early memories are from that period but don't involve events I can assign a date to?

I kinda suspect this is true for a lot of people, but since memories aren't time-stamped, they don't realize how early they are.