I figured it out when I was 11 years old. I saw my erect penis and noticed the tissue looked a lot scar tissue. It did not feel right either compared to the tissue at the bottom. A little numb and desensitized. It felt like it had been hurt and did not get better. It did not respond to stimulation, unless it was rough. I asked my mom about it and she told about circumcision for the first time. :(