You could describe the feelings you had that you think might be romantic.
You could describe what about the person you felt attracted to, or what you think triggered the attraction, or what you wanted to do with the person.
You could describe how often or in what circumstance you think you are feeling romantic attraction.
You could describe the kind of relationship you want (or don't want). Some words to consider if you're having trouble describing the feeling:
glowing, safe, electric, warm, happy, calm, cuddly, desperate, longing, giddy, excited, curious, anxious, tense, loose, se