I think you are good to move on to the 250 boxes challenge but there are a few things you have to keep in mind from your lesson 1 submission. Here's my thoughts on your submission

Superimposed lines: very very well done. There is no fraying on the start point and the lines are very smooth overall. The smoothness of your strokes is a strength that carried on well to your ellipses. Much better than average i must say for the superimposed lines.

Ghosted lines and Planes: You do an okay job with your lines but you can easily do much better. Your lines don't wobble per se but aren't straight either (especially for the longer lines). They are smoothly arced, almost too smoothly. There could be 2 reasons, the first being you are using your elbow and not the shoulder. One easy way to check if you aren't drawing from the shoulder is if you dont feel your elbow moving at all (as in the physical location of the joint not moving). The second could be you're naturally predisposed to drawing arcs, so try correcting for it by visualizing that you are arcing your lines the other way

Ellipses: They are all well done nothing much to say. You've done everything the lessons required. Only thing you need to do is to continue practicing them so you can work towards having tighter ellipses.

Boxes : Again over here, you have done everything the exercises required you to so i don't have any specific critiques to give here. But they arent perfect mostly because of your line quality. I would say that most of the bad line quality came from the sheer frustration that doing a box takes so long (1 box is 12 individual lines after all). Take your time while ghosting every single line. Patience is something that is an absolute must in this course.

Moving forwards, keep practicing ghosting lines and ellipses, you will eventually get better at your lines.