RRD, I'm not sure if role playing counts as imagination, but if it does, then I think she's probably got a big imagination, given that I've been 'Owlette' and she's been 'Romeo' (from PJ Masks) for nearly a week now. She doesn't drop character, and corrects me if I do. :p
Role playing absolutely counts when it comes to imagination!
As for getting her evaluated, I suppose it can't do any harm. But I doubt any professional would diagnose her with ADD (or anything like it) at her age, nor do I think you should worry yet (she's only 3!). Of course, I'm a mom, not a professional.

With DS6, over time, it has turned out to be his intensity that meant he would rarely stop moving. These days, his intensity is what sometimes leads him to focus on an activity for hours on end.