Trying to import songs onto CD but says not in MP3 format

So, I was trying to burn some CDs yesterday off of my iTunes and the blank CD was detected by iTunes - but once I created the playlist and clicked on Burn, it said that all the songs had problems with them because they weren't in MP3 format.

I went into the Preferences and realized that the setting that I had had it on when importing new songs into iTunes was not for MP3 so I quickly changed it. I reimported one of my CDs that I had bought a while back and replaced the files with the MP3 files and then tried to burn the CD and it worked.

I really don't want to have to do that with all my CDs that I had already put into iTunes by importing the songs. I noticed that there was a "Convert selection into MP3 format" option when you right click in the playlist but once I did that and tried to burn it- the blank CD wouldn't recognize it as MP3 format.


Please someone tell me that I don't have to reimport all my CDs again!!!!!