Short answers, pulled from the story.
The First Succession Act, passed in March 1534, declared Mary, daughter of Henry VIII and Catherine of Aragon, a bastard, and named Elizabeth, daughter of Henry VIII and Anne Boleyn, as heir presumptive to the Crown. It also required all subjects to swear an oath recognising the act and the king's supremacy.
The act was passed in March 1534, though it is formally titled the Succession to the Crown Act 1533. The discrepancy exists because the legal calendar of the period began the new year on the 25th of March, placing the act in 1533 by contemporary reckoning.
Anyone commanded to take the oath who refused faced a charge of treason under the Treasons Act 1534 (26 Hen. 8. c. 13). Treason carried the penalty of death.
Mary was declared a bastard because the act treated Henry VIII's marriage to Catherine of Aragon as invalid, thereby removing Mary's claim to legitimate birth. This cleared the path for Elizabeth, born of Henry's marriage to Anne Boleyn, to become heir presumptive.
The Second Succession Act reversed the First by declaring Elizabeth illegitimate. The Third Succession Act then restored both Mary and Elizabeth to the line of succession, giving each a legal standing they had lacked under the earlier legislation.
Elizabeth was born on the 7th of September 1533, making her approximately six months old when the act was passed in March 1534.