You can get away without it as I did yesterday, however I would suggest you update it anyway as I will also do later today.
I have only every updated a BIOS/ UEFI a hand full of times before and trust me it's very simple with modern boards.
Thinking about it, I believe ASUS, with AI Suite 3, has a BIOS update tool so you can do it from I windows (don't quote me on that). There are also many tutorials on YouTube showing the entire process and I'm sure you'll be fine.