|"NTFS is supposed to be more efficient so I'm thinking of converting it"|
It's not going to make your system run any better or any faster if that's what you think. There are reasons to convert...smaller cluster size which results in less slack space, network security, the need to work with files larger than 4GB. If none of those things are major issues for you, I see no reason to convert. You have a working FAT32 partition, there are risks in performing the conversion. Make sure you back up all your important files before doing so.