So it looks like you will indeed need a BIOS update, per
https://www.wepc.com/tips/bios-update-for-new-ryzen-3000-chips-x470-b450/
But that should be extremely simple if you have an existing CPU that is compatible with whatever BIOS version on your motherboard.
Sans that, it is nearly as simple if you have a Q-flash/other flash button on your Mobo that you can press after sticking a USB with the updated BIOS into the primary USB port (per Mobo manual).
Barring that, you should be able to flash the BIOS of your B450 motherboard using only slightly more advanced/complicated methods, although you'd need to google those instructions.
But it is all very definitely possible, and if following instructions, relatively simple for a lightly/reasonably tech savvy person.