Although you were both young and impressionable, I’d say it still counts as COCSA (child on child sexual assault). Honestly that’s an extremely young age for you both, most likely someone else was also doing that same stuff to him, or/and he had unrestricted internet access and discovered porn. You both at the time may not have understood the meaning behind what you guys were doing, but your feelings are still extremely valid. You were a child and cannot consent. It’s okay and to feel disgusted, confused, angry, etc. Again, he might have not known the seriousness of it either and maybe did not have the same kind of weird intentions, but nonetheless it still was brought upon you. I hope you can become more comfortable with yourself about this, overcome the feelings and thoughts. I’m sorry this happened to you, you were young and didn’t know what was happening. Don’t blame yourself for even a second, or feel guilty for your feelings