Fenny,
Time is normally positive and should start at a smaller value and get bigger. In this case, you could take your data into excel, add the first value all of the time values (0.0206154) and the resulting column would work fine. I am not sure how you got time to be negative unless you were measuring from a point in the future as a reference.
There is no limit (that I have found) to the number of points. But the time column must be ascending and cannot be negative.
Britt