Hi Millie, welcome to our little bunch of mapping misfits.
Great start on that map! Interesting layout, rivers look good, and I like the coloration. The mountains that you've got over on those islands in the SW look pretty awesome.
The only two nitpicks I have are 1) the TOO sharp sharpness of the continental shelves/underwater landforms compared to the (in my opinion) much nicer soft blur land stuff; and 2) I think your landmasses could benefit from a thin stroke, maybe in a dark blue color.
Have some rep for posting a map right off the bat!