You are doing the right thing by asking! It is a good idea to read that first thread. When I was starting nursing school, I had the same goal of becoming a crna, and now that I'm in anesthesia school I can hardly believe it! While in nursing school, I always kept it in the back of my mind. When I didn't feel like studying, I would motivate myself by believing I needed an "A" to get into anesthesia school. I also made sure to take a statistics class. I wrote papers about pain management and crna issues whenever I could chose the topic. I also went right into ICU as a new grad (don't let everyone tell you it's a bad idea - many people do it with no problem). I would also email the anesthesia schools you are interested in attending and ask for admission info. That way you can know exactly what you will need in the future! And shadow a crna if you haven't already. Then you can see exactly what you're getting into.
Good Luck and study hard!
Jay