I would go by my gut feeling and start slowly to see how she reacts on it (milk intake, milk cut back, digestion, poo, wind...)
if everything is fine and she doesn't cut back on her milk intake, or not too rapidly, I would go on
that is what I did with Juleika, I always made sure she is still drinking enough milk and kept a close eye on her digestion
if she does cut back on her milk intake or gets digestion problems, I would wait a bit longer
but please note, these are only my mummy guts, can't guarantee that this is the right advice, though
