Cecilia Weston

The History of Parliament page for Robert Weston lists John Weston and Cecily Neville as his parents and says: "Although the published pedigrees disagree as to whether Cecily Neville was Weston’s mother or grandmother, what little is known about Cecily establishes her identity with Weston’s mother. PCC 25 Peter; N. and Q. (ser. 4), iv. 367; Emden, Biog. Reg. Univ. Oxf. 1501-40, p.618."
The History of Parliament is an extremely reputable source that for decades has conducted extensive research on historical members of parliament, and if they have concluded that Cecily Neville was the wife of John Weston and the mother of his children, then I think that's fairly convincing. The main objection I've seen to identifying Cecily Neville as John's wife is that it seems unlikely that the daughter of Ralph Neville would have married someone of John Weston's social status. But the researchers at History of Parliament, who have studied and researched British history for years, apparently don't think it's that unlikely.

Source: The History of Parliament: the House of Commons 1509-1558, ed. S.T. Bindoff, 1982. Link to entry in online database: https://www.historyofparliamentonline.org/volume/1509-1558/member/w...)

Biography

https://www.wikitree.com/wiki/Neville-1904

Cecilia Neville was the daughter of Ralph Neville, Lord Neville by his second wife Edith Sandys. Her parentage is known from a College of Arms pedigree created for Richard Weston, 1st Earl of Portland in 1633.[1][2] Included in the 1633 Weston Pedigree is a letter from Simon Weston where he details his ancestry including naming own grandmother as Cecilia Neville, daughter of Ralph Neville, Lord Neville and a sister of Ralph, 4th Earl of Westmorland. Also found in the pedigree is a grant of land from John Weston of Rugeley to her husband and Cecilia also name her father as Ralph Neville. Outside of the pedigree, evidence includes the funeral certificate of Sir James Weston which also states that his grandmother was Cecilia Neville, daughter of Ralph Neville, Lord Neville.[3][4][5] The Neville arms are found on the Weston monument in St. Mary's Church in Litchfield.

The 1633 Weston Pedigree and Cecilia's very existence has been challenged as a fabrication. However, the overwhelming evidence points towards the accuracy of the pedigree, and the flaws with conspiracy theories challenging the pedigree. Read more about these issues here.

She was likely born about 1491. Her parents were married in 1490. When her father died in September 1497, her mother was pregnant with her brother, the future 4th Earl of Westmorland.

Cecilia was last known living on 15 July 1526 when John Weston of Rugeley gifted land in Lichfield to John Weston and Cecilia his wife.