There are multiple types of memories, so to speak.
We have our conscious memories, where we can recall details about an event, like, "I drove to the store, it was in the morning, it was cloudy and I had REO Speedwagon playing in the car."
Then we have subconscious memories. Subconscious memories manifest often as emotions, physiological responses and so on that often don't seem to make sense for a situation. This is because while we do not consciously remember something, our subconscious does remember. One of many ways this could manifest is as a CSA survivor never feeling comfortable in clothing that isn't baggy or concealing. You might see her wearing a large sweater even in the middle of Summer. She might not know why she feels a strong need to cover up all the time, but her subconscious knows.
Even our body has its own set of memories. For example, a survivor of childhood sexual abuse might not have any conscious memories of it, and they might not notice any subconscious issues coming forward. Perhaps they were only an infant when the SA occurred. And yet when they try to be intimate with a partner, they discover that they have vaginismus. Even though they are aroused and relaxed and want to have sex with their partner, their body is saying NOPE. Their body remembers something that they do not.
So very often, even if we were far too young or dissociated to be able to form detailed, conscious memories, there are often other signs of memory to be noticed.
