Upgrading from Sierra to High Sierra from fresh USB install HFS vs APTS

I built a hackintosh back in 2017 with the help of a hackintosher guide and clover. I built it into Sierra (10.12) OS.

Well this past month it broke because of the nvidia driver expiration issue, and from what I can tell, the most straightforward way to fix it is to install the re-signed drivers, and to install those I need to upgrade to High Sierra.

CPU: I5 7500 (Kabylake) GPU: Nvidia 1050Ti Mobo: GIGABYTE GA-Z270MX-Gaming 5 LGA1151

Wanting to do things more properly now, I just followed the opencore guide to generate a fresh USB stick with high Sierra. My question is about the HFS+ vs APFS file system upgrade between these two OS versions.

If my existing hackintosh hard drive uses Sierra OS (10.12) and HFS+, and I try to install high Sierra (10.13) from a USB stick, will I be upgrading the existing Sierra install, preserving the data structure, and changing to an APFS file structure automatically? Or will I need to reformat my entire drive before attempting to install high sierra because the existing data is HFS+?