Thanks for reaching out. When you sign up for a Pro Twitter Stats account we start recording your Pro Twitter data. Twitter Counter cannot display statistics for data that was not recorded. However, we try to get as much Pro Stats for your account from Twitter. Unfortunately, Twitter also has to deal with system availability. Which means in some cases we can't retrieve historical Pro Stats at all (but most of the times at least a couple of days).
Since you've just subscribed to our Pro Stats service, the first 30 minutes you will only see the CSV files from the last 30 days. However, we will store all the information we're able to get, so next month you'll have a complete and very accurate CSV file with all your Pro Stats from the past month. If we've been tracking you before we will show more basic twitter stats on your export stats page, this process may take up to 5 days.