Not just among Twice but even in the industry itself, it is hard not to notice how well Mina is maturing. It doesn't mean the others aren't aging well, I just feel like Mina has the kind of beauty that will blossom even more in her 30s and 40s.
Aside from Mina, I'd probably say Nayeon, Jihyo, Jisoo, Joy will also age pretty well, and of course Irene who is already in her 30s.