I'm glad you're enjoying it! The classes are more so for different dialog and story options down the road. My goal is to not restrict character romance options by class.
Depending on the class you choose you may spend more time with a character of the same class, but you will still be able to romance any character(s) you choose.
For instance, you can be a mage and still romance Orion or Reth or any other character, you won't be restricted to only choosing Silas(you will likely have more interactions with Silas as a mage, but will still have opportunities to be with others).
Two of the options are currently closed off since I didn't have character sprites for the characters that share those classes. In future updates I'll be making them selectable (with dialog saying if they are not implemented yet) to hopefully cut down on confusion.