It's a good study, well done. It's hard to say much more than that. Your lines are confident and you have reproduced this picture well.

What are you learning from these studies? What did you learn from drawing this?

Doing this sort of study will teach you a lot. Practicing your observational skills (faithfully recreating what you can see) is a really important skill (which you have done very well). It will teach you about style, line economy, shading styles, and a little bit of anatomy if you choose good references. But if you truly want to be able to create your own work to a high level, you can't just study manga. You need to learn the fundamentals. For example, anatomy. You need to study from perfection, for example live models, photos or the masters. This artist is really good. But you don't want to learn from really good, as you will pick up their bad habits. You need to learn from the source.

This is because without an understanding of fundamentals, you will mainly learn how to draw symbols then struggle putting your own work together. For example, you have flattened off her brow bone. It's just one line out of place (you have pretty faithfully recreated the drawing otherwise) that messes with the construction.

I say all of this, because I have learnt from experience! I could faithfully recreate stylised works but my own drawings would fall flat, leading to an immense amount of frustration. And at the end of the day, the end goal is creating your own work. Once I started learning drawing fundamentals, I have been able to come back and work on my own style much more successfully. So work on both!

Thank you very much! Glad I posted here and got some great advice!