I can already tell this is a Campaign Cartographer 3 map - I recognize the standard overland symbols you've used. And obviously the Crossroads Inn is your home base for your adventuring party.

The layout isn't bad. You're not breaking any River Police rules.

My only question is the dark green area around the central river and on the coast - is this supposed to represent a drop in elevation, like a valley for the central river.

If that's the case, the two rivers that merge with the main central river are dropping from higher elevation into the valley. Which would mean your rivers should flow 90 degrees to the contour lines, instead of what you'd normally expect how a river should merge (like your existing version.) What I am saying is if the rivers are dropping into a valley they should point almost directly to the central river flowing gravity towards the river valley.

Otherwise, you need to create slight valleys for each of the two side rivers that merge into the larger valley then merge into the central river.

The "yellow things" at the delta mouth of the main river - are those islands, they look like giant rubber ducks, maybe you should make them green like the rest of your land, so they better match.

Also, what is the scale supposed to be. Those rivers, especially the west river is awfully short length wise.

Still not as bad a job as you think, some corrections may be necessary, but you're not too far off.

GP