Yes, it's said that the padjal stop aging when they're 'chosen' by the elementals and are transformed into a padjal, so it's likely that this can happen at any time in a padjal's childhood while they're still a hyur, even in early puberty, which is probably the reason why Kan-E-Senna looks a little older than the other padjal, but still very much physically undeveloped - she was just 'chosen' by the elementals a little later in her life.