I was 14/15 when I realized I was aroace, but looking back the signs were there before then. It's been a few years and nothing has changed. I would say if you feel like you're aro, then you are. It's kind of like a hunch. There's a good chance it won't change, and if it does, then so what? If you feel the label aro fits you now, then you're aro. If you're old enough to recognize that you might be aro, you're old enough to be aro.