Abuse: Use of an object in a way it is not supposed to be used and which may harm said object.
A (non emotionally laden) example of 'tool abuse': Using a pocket knife to pry. Pocket knife blades are not meant for prying. As a result you can brake it, or bend or chip the blades tip. Abuse does not mean that it necessarily will get damaged. The core of the definition lies in the way the knife is used, compared to how it is meant to.
Apart from all that is wrong with the objectification of persons, the same can be said for sexual abuse. Frankly, it does not really matter whether I would have been cooperating or not. It even does not matter whether I wanted or asked for it (which is also part of the intricate social micro-system that developed over time and facilitated the abuse). A child is not meant to partake in an extensive sexual relationship, because mentally, it is simply not ready for it.
Don't get me wrong, I do believe it is common for children to have some sexual feelings from quite an early age and that it is normal for them to show behaviour accordingly, but all this is to learn and to establish a healthy sexuality and understanding of sex later in life. Since I was in over my head from age 11, without any of the understanding I have now, it was all together different. This simply was abuse.