Here is my problem. I am using Play2 Framework right now and it's providing me with Ebean as my default ORM product. I know Java fairly well and decide to write a website using Java, but I also want to learn Go, and ultimately change my websites' backend codes to Go (Go's framework Revel). I know my data will still be there, but I will have to use a different ORM product to rewrite all the models. Will this cause a problem even though I maintain the same exact database structure?
It depends on what's your definition of 'problem'.
ORM frameworks provides facility to map database information (relational data) into OOP object. Variation exists between ORM frameworks as to what DBMS they support, default naming rule when mapping table/column name to class/field, update cascading, transaction management, cache management, SQL translation etc.
You can keep your database schema and map it using different ORM, above is just some problem you might / not encounter along the way