Both, kind of. You must have your one month anniversary on the forum before the first day of the program period. For example, since this month's program starts on May 1, you have to have joined the forum before April 1.

I phrased it that way because your application date doesn't matter. So if you joined March 31 and you apply April 18, you're still eligible since you'll have been a member for a full month before the program starts May 1.