No, I'm not implying that mid-30s or 40 is too old for the youth part. It certainly wasn't for Peters at the time. But if memory serves, the youth part was dropped for Laine on the tour (as it needed to be, although she looked great but she was 61), and although my memory is less sure on this, perhaps also for Nancy Dussault.
All I was saying is that Joaquina Kalukango is quite old enough for the role, and you seemed to be saying that you thought she was perhaps too young.
If Beanie Feldstein had not done Funny Girl, she might have made scored as a replacement Baker's Wife. That is a role for which she seems suited.