yea...in winter...when i used to drive with my car still kind of cold....my car used to shake in 1st...but as it warmed up it was fine!

i think its just the coldness...nothing else to worry about.
my master cylinder for teh clutch is also bad (you can tell by lookin under teh clutch pedal, you will see a rod going thru the firewall of the car, if it is leaking, you will need to change it) but that didnt' cause shaking...it just doesn't let teh car go into any gears and leaves me stuck in neutral