Mrs. Goddard’s School is believed to be based on the Reading Abbey Girls’ School in Reading, Berkshire. Jane Austen attended the school with her sister, Cassandra. The Austen sisters attended from 1785 until 1786. The Reading Abbey Girls' School operated from 1755 until 1794. 

Image: Part of a painting by Paul Sandby of Reading Abbey Gateway via Wikimedia Commons. 

Source: Emily Zarevich, “The Reading Abbey Girls School” from JSTOR Daily.