I think it's clunky, a bit like
Roberta.
This comment in the comments is also what I immediately thought: "This looks like a weird concoction. Why not just call someone Adama?" Adama has more appeal to me if I really wanted a female version of Adam...and I don't. Although I do like
Adam as a name for a boy.
One of the other comments equates
Adamina with both
Jamesina and
Thomasina but I find
Thomasina much more appealing and it has a more natural flow than the other two.