I feel that both Aryan and Imlie fell in love with each other on the same day. As audience we were more in sync when Aryan hiccuped for the first time and called her cute. He pocketed the payal like all ITV heroes do. So we knew exactly the moment when Aryan k dil mein baaje guitar.
Fir Imlie it wasn’t made that clear for audience because she was still in phase of coming out of heart break. She was still coming yo grips with her divorce, her ex-husband getting remarried and trying to just keep swimming. But there was this moment when Aryan comes and holds her hand dressed as Raj. Pickd up her chit from ground and reverently kept it. She danced with him and looked so happy in that moment.
When she closed her eyes that was thr first memory if Aru that cane in her mind. The way her heart was so messed up it took her time to realize it.