It is possible to enable EFI-mode booting, but you'll need to install an EFI-mode boot loader to get it to boot. There are numerous ways to do this, and which is best depends on certain details of your configuration, such as whether you're dual-booting with Windows. See my EFI Boot Loaders for Linux page for information on available boot loaders and installation methods generally. My rEFInd is likely to be easier to set up than most, but I can't make any promises without knowing more about your current configuration.
Installing an EFI-mode boot loader is unlikely to do damage by itself, unless you're dual-booting with Windows and accidentally damage the Windows boot loader. OTOH, the benefits will be slim. The biggest likely benefit is a reduction in a few seconds of your boot time, but even that's not certain.