Short answers, pulled from the story.
Lady Jane Grey was born sometime between the 2nd of May 1536 and the 2nd of February 1537. She was the great-granddaughter of Henry VII and the grandniece of Henry VIII, placing her in the very heart of Tudor bloodlines.
Lady Jane Grey was proclaimed Queen of England on the 10th of July 1553 after King Edward VI named her his successor in his will known as the Devise for the Succession. She was summoned to Syon House on the 9th of July 1553 and informed of the King's death before accepting the crown under immense pressure from her parents and in-laws.
Lady Jane Grey reigned for only nine days or perhaps thirteen days if counted from the moment of Edward's death on the 6th of July 1553. The Privy Council proclaimed Mary as Queen on the 19th of July 1553, deposing Jane after her brief rule.
Lady Jane Grey was executed because of her involvement in Wyatt's Rebellion which was a direct response to Mary's intention to marry Philip of Spain. The government decided to reactivate the death sentence that had been suspended, and Mary signed the order for their execution on the 19th of January 1554.
Lady Jane Grey was executed on the 12th of February 1554 on Tower Green after her husband Lord Guildford Dudley was beheaded on Tower Hill. She was buried in the Chapel of St Peter ad Vincula and no memorial stone was erected at her grave.