You may want to verify your hardware is XP compatible many new system wont run XP due to lack of drivers, if thats the case then you would want/need to run xp as a virtual machine.
Linux Mint will install GRUB. On boot you will always be given a choice to pick the OS. As for XP, I would recommend running it in a VM, provided your PC has sufficient specs.
You may want to verify your hardware is XP compatible many new system wont run XP due to lack of drivers, if thats the case then you would want/need to run xp as a virtual machine.