i think chemistry is more important than age, but if i had to choose then hmm older LI i guess, i feel like they are more dependable cause they got more experience and knowledge. For the same age, kinda hit or miss, then again i like osananajimi troupe mostly if they get jealous from the new guy or how they have second male lead syndrome lol. For younger li they're cute, most of the time not really my type to choose for romance but more like must protect type.