My earliest memory is from around age 3 or 4 and it is of me dancing with my dad. My dad loves ballroom dancing and he and my mom used to put on old classical records in the family room and dance to them. My dad would pick me up and he would dance with me and my sister. There's nothing super extraordinary about it, but it wasn't just a one time thing and I think that's why it's solidified in my memory. My identity is not the same now because all the experiences I've had since then have shaped me.
Most of the posts on here seem to be about either strongly positive memories or strongly negative. It seems like the valence of memories doesn't really matter for strength of encoding, just the emotional strength. Just a thought.