I'm trying to pull the Follower Count from the first of every month, compared to a year ago.
There is no comparison feature on the Twitter Data Source. I can pull the current follower count, but not the count from 1 year ago.
Sadly it's a restriction from the API itself. The public API for Twitter only reports back a lifetime total for that value, taken when the query is run. It can't report them over time or from a specific time-frame.
You can use this setting to compile your own historical data - check this and then have the query run once a day to build a table of values over time.