I don't know if there is an officially recognized answer to this question - but i'll give you my opinion and experience and feelings about it.
my take on it is - YES - it is possible.
it sounds like you were less knowledgeable and more inexperienced in what you were being initiated into. he was sadly more precocious in his age-inappropriate experience. so he was in a position of greater power or influence and apparently pressured you into activities that you were unprepared for and did not understand or seek or desire at the time. this definitely sounds to me like abuse. he may not have intended it to be harmful to you - but the effects are more important than the intentions, from my perspective.
one of my abusers was a boy the same age as me. we were both 11 and it started toward the end of 5th grade. he wanted to "educate" me in everything he knew about s3x. it started with talk then progressed to both of us showing ours to each other and then to him touching and stimulating me to arousal. (I did not ever touch him or anyone else.) to the surprise of both of us, I was much more developed than him. I became an object of interest and curiosity and he shared the news and I soon became a freak show and toy for anyone in our grade and the ones just above us in middle school who wanted a look and a try at me. though I was the same age as many of them, and more mature physically than most, I was also more sheltered and ignorant of s3xual matters and therefore more vulnerable. I had also been conditioned by a step-dad (the 1st abuser) to be compliant and passive - so I was prime victim material. I see what my peers did as abuse - also bullying - but with a specifically s3xual aspect to it as well.
does that help you at all?
"Tell your heart that the fear of suffering is worse than the suffering itself... And that no heart has ever suffered when it goes in search of its dreams, because every second of the search is a second's encounter with God and with eternity." - Paulo Coelho