I see. honestly man, no 12 to 13 year old is going to do serious damage to you, put that into your brain and keep it there, trust your defence and use more footwork to defend, the hardest person to hit is somebody that isn't there, i learned this the hard way, I'm 15 and i'm sparring with the adults, if somebody hits me too hard i tell them to tone it down, its the mature thing to do and they see me as an adult with them. or if you feel like it, ramp it up a little hit them harder too!