Sounds like you'll do great! Keep listening! I tell myself that I'll never be much good but I can always get a bit better. Also, depending on where you are in MA I wouldn't be surprised if there is a good accordion teacher around who would teach you by ear...maybe ask at the session you've been to? Or email someone at the Button Box? If you can do it, a few lessons are amazingly helpful.
If you listen to a lot of CDs I bet you can learn by ear more easily than some people. I taught myself to learn by ear just by listening to a slow tune on a cd and making awful awful noises for a long time till I figured it out (I lived alone at the time). (Note: this method has not been clinically tested, and there perhaps are more effective ways to get started?) I also played Christmas carols by memory. It's the season where you can do that and it's semi-legitimate!
Also, check this out:
http://www.clare.fm/music/ClareFM%20trad%20archive It's super cool radio shows to download and just listen to when you're doing whatever.
Have fun, listen lots, and learn more cool tunes!