Welcome to the guild, and yes, this is addictive. That's a nice first map - serviceable and even pleasant. If all the narrow lines are intended as rivers, you need to take a look Redrobes' marvelous tutorial on How to get your rivers in the right place. If some of them are roads, maybe you don't have water running uphill, but in that case you'll need a way to distinguish between the two feature types.
Map in very first post equals boldness and a willingness to dive in, and is worth a smidgen or rep all by itself, so have a bit, and thank you!
Too big ? Naaaah. I think the upload limit is about 4Mb. The bigger the better, to the point we can see what you're doing and advise and suggest. 10x that would be overkill, true. What size original file are you working with?
These novels - done, or in progress, or in your heads?