It's not that she is that much older in 2.1
But it's because in every scene we saw her in during 1.0 it was in an echo, when she was a long younger (after all Minfilia was still a child)

So count not just the five years between 1.23 and 2.1, but also what cuold well be ten years between you seeing her in the echos and the present of 1.23