I can sort of relate to this. After I was diagnosed and put on medication, it was like my entire life became clear. I looked back and realized why my middle school and beginning high school life was so bad. I was totally impulsive, I interrupted people, I couldn't stay on track in a conversation, I was always moving from one thing to the next and interrupting people's games/conversations/etc, I said the wrong things at the wrong times, I didn't appropriately react to what people said or I didn't react at all, etc. So yeah, I guess I lacked self awareness.

But I don't think that a person with ADHD lacks self awareness. I think that they have it but its impaired. For me, I just was so distracted that I didn't really stop and think much longer than a couple seconds. So I acknowledged my feelings and the feelings of those around me, but I just didn't respond accurately because I was on to the next thing.