How will she use her closet? just clothes? toys? does she play sports? a musical instrument? are any of those in her near future?

Inventory everything she will store in there and other ways she might use it.

Measure the closet meticulously.

Then, check out The Container Store for closet planning. It is easy to install (I am not handy, the only time I ever used a drill was to hang the tracks in my last three homes including this one).

Their Elfa line has drawers, shelves, hanging, racks, hooks, and it is all adjustable as she grows (although, tbh, I never did end up adjusting my youngest's closet).

Thank you for your advice!!! :-)

Have you done a search for ideas? You can find MANY - then you need to decide how you want to divide up the space.

A system that is adjustable might be a good idea since she's only five now - and her needs will be different when she's older (although both of my daughters' walk in closets never changed over the years - and I never felt like I needed to change them - the builder did a pretty nice job whenn adding the built-ins for both closets).

For example, this one can fit a 69" - 95" wall:

It includes everything shown (except baskets) - $659 on sale for $221. Wayfair - over 2,000 4.5 star reviews.

You need to draw out the shape of the closet - you could then figure out possible designs. It's too difficult to come up with something specific without knowing any details.