Hello! I know I'm late, but I had to say something. It seems to me you might have misunderstood how the whole aromanticism deal, or orientations in general, work.
Being aro is about attraction, not action. Choosing not to date is not the same as being aromantic, just how choosing to get into romantic relationships doesn't make you automatically allo. Aromanticism is a huge and complex variety of experiences, but none of them ever cite their lack of attraction as a choice.
As for you, maybe you only realized it recently or it changed overtime (yes that can happen), or you're an allo who decided they're happier not trying to pursue a relationship. These are possible explanations that I could think of and given the sheer breadth of the aro experience, there might be other explanations, but I'm not going to pretend I know more about you than you do. Either way, these are all perfectly fine ways to feel and I'm happy you figured something out for yourself. Just calling being aro a choice does not sit right with me.