Macs have been 64bit computers for over 10 years. You are posting on the High Sierra community, so if you stay on High Sierra
you will still be able to use your 32bit apps, all macOS's from Mojave 10.14.6 backwards will stay the same. There is not an event happening soon that will render everyones Mac as incapable of running 32bit apps.
Apple will release macOS Catalina 10.15 in the next few weeks and it is this OS that will no longer support 32bit apps, you are under no obligation to install this, you can keep running High Sierra and using your Epson scanner. If you do want to install Catalina you can also keep High Sierra either on another partition on your internal drive or install it on an external drive, and boot between the two using System Preferences> Startup Disk.
Epson is the only one you can give you information if the are going to update their drivers to 64bit, or see it as an opportunity
to sell their latest products.