Thanks again, I've fixed it.

2. Yes, i have understood from details that for January always "You are on track." must be returned.

Thanks Daniil for your comment.

1. I've fixed kata's details.
2. What do you mean exactly? Do you suggest that January is a special case and we should hard-code "You are on track."?

There are inconsistencies descriptions and tests:
1.
In details - "You are 3 ahead of schedule!"
Test requirement - "You are 3 ahead of schedule."
2.
In details - count only the item for completed months (i.e. for March check the values from January and February) and it means that for January you should always return "You are on track."
Test requirement - process January as other months and suppose that we have 0 pledges requirements for January