Why does car have to warm up before going into drive?
When car is first started it will go in reverse but not drive. After warming up for about 30 minutes it will go into drive with no problem.
That's not 'normal' and should not happen. I wish I had an answer for you what the problem is but I can say that much with certainty
Cold weather makes oil very thick but as it gets warmer it get thinner (Kind of like vegetable oil... it's thicker when cold but the hotter it gets the more it flows) however a transmission works in all weather so I will look for the easiest thing first. If your car has high mileage perhaps you should have your trans fluid and screen changed ... it should not be expensive and you may get a free transmission inspection