Depends on the shape. If you pruned her bonsai style, she should never be more than 8-10in high IMHO. Just judge ny looking at the prospective cuts. Are they well formed? Not a light green shoot off with a few really light curled leaves. Make sure they are nice n healthy with at least 3 nodes on it. There is no set height she should be first. I have taken cuttings off a plant 3-4 weeks old, and then cuts off of that cut 4 weeks later. Hope that helps
whiskeytango