Hey! I can sort of relate to what you were saying, I felt the same way when I was questioning. I realized I was aromantic when I was 14. I don't think you can be 'too young to know' if you're aromantic. If you feel like the label aromantic suits you and you feel comfortable with it, then you should use it. Keep in mind that your romantic orientation might change in the future, and that's ok and totally valid. I think it's important to find labels that suit you, while understanding that there's the possibility that they might change.
Good luck, and I hope you're able to figure this out :)