I am greyromantic, and have been for a number of years. Here are my observations for realising I was:
Besides obviously rarely experiencing romantic attraction, I also noticed that if I did like someone, the attraction would feel rather 'weak'. People would describe their romantic feelings as rather intense, meanwhile mine were quite less in comparison
Not knowing the difference between platonic & romantic feelings. "Does this person like me that way? do I like them back? I cannot differentiate and I am not going to try!" It also doesn't help I'm questioning if I'm aplatonic, but that is a story for another day Also I'll often 'forget' I like someone, then my brain is like "Hey remember that person? They're cute" and I'm like "Oh yeah.. I do have a thing for them, don't I?"
Not actively perusing romantic relationships, regardless if I like them that way or not. This also may tie into the fact I'm neurodiverse as well, affecting the way I socialise with people could also be another factor. Dating websites don't do much for me either, though I have used them, I want actual relationship with feelings and not one where I'm lying about my aromantisicity to make my partner happy
Romantic culture doesn't always make sense to me. Maybe it's just me but my ideas of dating are different compared to most people, I'm not a fan of fancy stuff people do on dates and such, I prefer some quiet time with my partner or space to myself. But I also feel like I don't fit within aromantic culture, but that's another story