Asexuality is where you don't experience sexual attraction. You might be able to differentiate between the others if you experience sexual attraction (that is to say, your body reacts appropriately to other people and deep down a part of you wants to be sexually active with other people) but feel scared or sick of going through with certain acts or you feel uncomfortable with the idea. On the flipside, many asexuals do feel uncomfortable with the idea of participating in sexual acts because they are not sexually attracted to any partner, but that is not a requirement for asexuality as many other asexuals are comfortable with or even enjoy sexual acts.

If you don't experience sexual attraction, even if that does have a basis from abuse or if you find that your feelings change in the future, if asexuality is the label that suits you now, there is no reason not to use it and no one is going to fault you if another label suits you better later.