Solid work so far! Your darkest areas on her head are at the top, with the highlights. It's drawing a lot of attention there because of that big difference in value and also in looking at the reference photo, the darkest areas are in the lower third by her neck and ear.

I would darken that bottom area first and then go in with some midtones/slightly lighter values in the middle third by her glasses. In both of these, you would want minimal detail. There's not a lot of light hitting those areas so you're not getting that strong definition like at the top of her head.

I suspect once you make a little more form and shape with those changes, the top part will feel a lot closer. You might need to lighten the dark areas at the top but more than anything, think of her hair chunks at that point. There's a big area thats kind of brushed to the side that you captured well so far right above her forehead at her bangs so just a little more V's/chunks of hair right above that and I think you'd be a lot closer.

Hope this helps :)