Well, there is an error in your line of code,
please change it to:
as your data is in AA column and not in AB column.
Now come to your issue for the first few values are not rendered onto charts, it is not the issue with Aspose.Cells rather MS Excel’s behavior. For confirmation, you may create the same chart using the file “Input.xlsx” manually after inserting the data into AA column’s respective cells, you will see in the first part of the chart, data is omitted and empty, so it would be also same as the output chart (you attached the output file) generated by Aspose.Cells APIs.
If you still think other way, kindly do create the chart using the file “Input.xlsx” manually (after inserting the data into AA column’s respective cells), save the file and post us here with steps details and screenshots, we will check on how to do it via Aspose.Cells APIs.