How to refresh ag-grid data after deleting selected row

You need to use the grid builder. It will be something like this:

1) Import gridoptionsbuilder

from st_aggrid import AgGrid, GridOptionsBuilder

2) Make object (and apply the settings you like)

gb = GridOptionsBuilder.from_dataframe(loaded_data)
gb.configure_default_column(groupable=True, value=True, enableRowGroup=True, aggFunc='sum', editable=True)
gb.configure_selection('multiple', use_checkbox=False, groupSelectsChildren=True, groupSelectsFiltered=True)
gb.configure_pagination(enabled=True)
my_gridOptions = gb.build()

3) Apply to Aggrid

new_dataframe = AgGrid(loaded_data, 
                       gridOptions = my_gridOptions,
                      update_mode=GridUpdateMode.MODEL_CHANGED
)

See the link for all details