What if I just haven't met the right person yet?
If you're asking this question, then you're very likely on the asexual-spectrum somewhere. For most people, sexual attraction is not an exceptionally rare emotion, and it's a feeling a you can have without the other person necessarily being the perfect match for you. Allosexual people almost always experience attraction to more than one person in their lives and they know what attraction is before they meet 'the one'. The very concept of 'the one' is a bit of a myth anyway. The reality is that intimate relationships aren't particularly rare, and they often aren't perfect either.
This is one case in which the concept of grey-asexuality can be very useful. Grey-asexual refers to anyone that experiences sexual attraction sufficiently rarely in comparison to whatever is considered normal. While not the same as (strict) asexuals, grey-asexuals often have many experiences in common with them, and the two are almost always grouped together under the asexuality umbrella.
If the number of people you experience sexual attraction to is so small that you've never met / seen one – so that you're wondering if you experience attraction at all – then you are grey-asexual. Most people do not go years or even decades without finding anyone sexually attractive.
You may also be wondering if it's typical to only feel sexual attraction once a relationship has already started and/or progressed to a certain stage – and perhaps you've never been in such a relationship so that could explain your lack of attraction. This genuinely could be the case: to only feel sexual attraction after a strong bond is formed is called demisexuality. Demisexuality is usually considered a form of grey-asexuality. This is because most people experience both primary attraction (i.e. attraction based on looks or other immediately apparent characteristics) and secondary attraction (i.e. attraction based on a strong bond, intimacy, or an emotional connection); whereas demisexuals experience only secondary attraction.
And finally, it's best to recognise in situations like this that sexuality can be complicated, and it can change. You don't need to figure everything out, make a 100% decision, and never change your mind. You can go with whatever label fits you right now, and if that changes, you can just take that as a sign that you're getting better and better at knowing yourself. And if no label fits you that's fine as well. Labels are just tools that can help you understand yourself. It isn't a waste of time to think about your experience just because you might not be able to come up with neat answers to everything right away.