Bear in mind that you are offering a print of your original work, so you could sell many of those as you want (unless you make an edition limit and use that as an exclusivity feature). I think you include labor in pricing for things like jewelry, which can be more easily measured. Thought, reflection, process of painting can take allot of time. After it's complete, and you make prints from it, I think you have to let it go. Price the prints to sell. If you choose to offer the original painting, then you think about what it's worth to YOU to let it go.
16" x 16" is a bit larger than most I've seen in the short time I have been on Etsy. I notice there are several artists selling 8" x 10" prints for approximately $20.00. So, you seem to be right in the ball park. Maybe a buyer will think they are getting a deal on extra footage with your stuff!
Don't worry about feeling so lost, we all feel that in the beginning. Patience, perseverance, and remembering it's a learning curve will help. See what works, and build on that.
Good Luck and have fun!