God damn it auntie why did you even said that its not like one of them is a minor

I think she wanted to remind of their age gap because despite Yeoreum being an adult, he is fairly inexperienced and it's his first love, so she wanted Hyeonseon to be mindful of the fact that if he plays with Yeoreum's heart, it could scar him badly

Because the age gap is still huge regardless of they’re both adults. it’s legally ok, but even in real life, when people on social media post their 15+ the gaps, the comments still question them even if they’re both adults. So see it as that’s how the aunt is perceiving them.