Frequently in computer programming work we will not understand all about a project until we begin implementing it. This is part the inherent or essential complexity of creating software described by Fred Brooks: "The complexity of software is an essential property, not an accidental one". Brooks found that prototyping software was instrumental in understanding a project's needs and problems. I have found Dr Brooks' insights to hold true, so I would recommend approach B. Otherwise you might be studying things you don't need to know (premature optimization).