Amazing work! Very detailed, and the line weight work is really on point!
Nothing to say about the piece itself, though I notced a very slight jagginess in some lines. What DPI/Resolution are you using? For these exercices, if done on purpose, low res is perfectly fine, however if you're looking to eventually raise that, A4/A5 (at 300 DPI) is usually a good spot, with higher res for more elaborate pieces. Also kinda depends on what your hardware can handle.
For very serious pro work, some will go for 5-6k.
Also worth keeping in mind res is not necessarily a fixed thing, you can start low, and increase as you need to (though it's not recommended to go from high to low).