Mulberries are a reasonably popular fruit among fruit enthusiasts.
There are many selected/named varieties of mulberries out there for sale, etc.
Wild white American mulberries, however, are not generally considered a desirable fruit tree to my knowledge.
(white mulberries, I think of different species/variety are, however, grown in Turkey for dried fruit production and are fabulous in my opinion)
If it were me, I would graft a dwarf mulberry variety onto it, such as Gerardi Dwarf. Wild mulberry trees get huge.
to your other question, yes It will produce more fruit as it gets older.