Susan,

You will need your green card number and green card expiration date to complete the application. Your I-551 stamp lists your green card number (starts with A) but I suspect it does not list your future green card's expiration date (my stamp does not). And you cannot assume it will be 10 years from the date of the stamp.

So for example, without giving away my personal data and so using fake dates, I might have received at stamp on March 11, 1999, my first green card says I was a resident since March 12, 1999, my current green card says I was a resident since April 14, 1999, and my current green card expires April 16, 2019.

If you cannot accurately predict your green card's expiration date, you cannot complete the application.