ur first class certificate is just an evidence of hard working. this is totally different from being  successful. there are lot of successful carpenters, welders,etc that employ a lot of first class graduate.
in nigeria setting, who u know and who know u is what determine how successful u will be. the extent of ones success is a function of how lucky one is. how lucky u are is determined by God. hence, your success is in the hands of God not in the hand of your first class.