Red, Yellow, Green, Gray automation formula help needed

I have a sheet with a drop down column, then a symbol column. I am trying to automate the color of the symbol in the symbol column based on the drop down choice selected in the drop down column.

This is the formula I'm using, but I keep getting "unparsable" back:

=IF([Estimated Days to Close]@row = "0 - 90 Days"; "Green"; IF([Estimated Days to Close]@row = "91 - 120 Days"; "Yellow"; IF([Estimated Days to Close]@row = "121 Days or greater"; "Red"))))

NOTE: I haven't added it yet, but the final color will be gray if none of the other conditions have been met.

Any help would be appreciated. Thank you!