If the Vatican had doubts about Lucia, would they not  doubt Francisco Marto  and his sister Jacinta Marto as well? On May 13, 2000, they were declared "blessed" in a decree from the Congregation for the Causes of Saints.  The doubts about Lucia have to do with the Third Secret, which many still believe has not been fully disclosed. I fully believe she will one day be declared a Saint with her two cousins.