New to the field

Appian can absolutely be learned without any knowledge of coding. The training materials do a great job slowly walking you through new concepts.

Appian is so unlike the majority of languages that only a little carries over.  Appian would probably be roughly as difficult to learn whether you already knew Java or not.  Which is to say pretty easy.

If you don't need to learn another language yet, Appian expression language is a good first.  The courses also provide you with lots of things you can do and build before you have to even start typing serious code.