Hey! Dont worry, you aren't too late. The regular decision deadlines for most colleges are around Jan1. In any case, they are postmark deadlines, so as long as you send it on the given day, youre fine.
However, it's always better to send them before hand - couriering them typically takes less than a week to arrive at most US colleges!
Relax. Chill. The deadline for sending the Transcript is, more often as not, the same as application deadline. And for Regular Decision most deadlines are 1 Jan. And that also means the post mark date and not the date to be received by colleges. As far as I know, most schools with counsellors send their packets in the 2nd week of December before the winter break.