Why won't it take my ago for last year

[biglebowski1128]

I assume you mean your AGI.

The first thing that occurs to me is that you may have amended your 2018 return after you filed the original.  This may have changed your AGI.  Use the amended AGI and see if that works.  OR, if you amended and are using the revised AGI now, try using the original AGI.

Good luck!