If your great grandmother was Etta Jane Lilly (1880-1926) who married George Henry Harvey then yes, she was of this Lilly line.
Want to swap information? I can offer you a chart of all of your Lilly ancestors back to Robert and Mary. That would include the 4 generations before your great grandmother.
In trade I would like information linking you to the family. How much is up to you but I would like to get you on the chart.