That's a pretty big deal. An 8 year old has formed their personality on all the experiences they had from birth to age 8. Everything experienced up until then has become a part of their being. Some of this is unconscious development (birth to age 3, and then some of 3 to age 6) but conscious development begins to occur from age 3 onwards (part of conscious development is awareness of self in relation to the external social world, including memories.)
Trauma obviously plays a huge part in this scenario. Memories prior to the accident were most likely consciously avoided because the emotional trauma was too overwhelming. Maybe it is even possible that a "new self" who had no connection to the old self was created, so that old memories didn't intrude upon new self and new self could continue on (mostly) trauma free.
But yes, I think its a huge deal. I think the trauma memories are buried in there somewhere and will come out when it is safe for them to do so. I also think its important that they do, because one would not be living a whole life without them.