That's an awesome first map! And I got a CRAP load of art out of my first entry level tablet, which was a 6x8 Wacom Graphire (so not the smallest cheapest one, but the least pressure-sensitive, with the least special features) I saved up babysitting money to buy as my first ever big purchase. You can do a lot with one. Of course by now I have a 24 inch Cintiq which is basically like a drafting table you can draw on (very recent purchase; did get it used though) so uh it is definitely possible to spend money upgrading but for what you did with this map what you got is great.
Anyway, I hope to see more art from you, glad you've upgraded from lurker.