having some trouble with the skirt and body😭😭

[golden coral]

I cannot stress enough the power of reference here. While this is an OC(?), elements can be referenced from different sources. I've taken the liberty of compiling some for you. You have a very clear concept and maybe these (or some like these) will help you nail down specifics. (Incidentally, these ruffles are usually called "vertical ruffles" or "vertical circle ruffles")
Furthermore, from a costume design perspective, it may help to consider how a garment would be constructed in reality in order to figure out how to render it 2 dimensionally. For example: the fabric, would it stretch? Is it heavy? Light? Stiff? Transparent? Does it have layers to achieve its silhouette? Now, for a fantasy 'fit, exact physical rules may not apply, but are still usually worth considering.
For a skirt this voluminous, I would consider adding a waistband or tie detail (or some other visible method of putting it on). The particular shape you're going for is great and unique--how is it being achieved? Dramatic petticoat? Weird train? Floaty magic?
So many things to consider, and all choices that could tell someone more about this character in a glance!

[golden coral]

Because I can't leave well enough alone, here's what my approach would be (knowing nothing else about your character--you know them best!)