Steph_anie, I'd still be curious to know what your priority/priorities for the weekend are. If skiing is the top priority, you can take a Colorado Mountain Express shuttle directly from the Denver Airport to any one of several ski areas. Discounts for a group of 3 or more people.

http://www.coloradomountainexpress.com/

I'm from L.A. and have no experience driving in extreme winter weather conditions, so I wouldn't even consider renting a car in December. But that's me.

The cost of a shuttle round trip for that number will be more than a car rental, I would guess. And once there, you are pretty limited in what you can do.
I also would like to really hear skill level of skiing and more of what you are interested in.
There are great restaurants in Denver, good museums, world class shopping (!!) and a lot of fun stuff nearby also.
Colorado is second to none keeping their roads cleared, IMO>\.\

[pretty sure you guys scared off the OP. Sometimes, you really do need to let go and move on.]

Completely agree. The OP didn't ask if they should go skiing over a weekend her words were "planning a girl's weekend...and definitely plan to go skiing" Then all kinds of assumptions are made and advice that skiing over a weekend for beginners is not a good idea. Many Fodorites ( and even I have been guilty) assume we know best and are presumptuous enough to ignore a posters request. Too make things worse there is a tendency to get absorbed in personal spats that certainly don't add anything to the post or to the forum. Seems the need to prove oneself right or make point is more important than helping someone who has asked a simple question

Personally I hope Steph and her friends have made plans for a weekend skiing. Sure they well have a good time unfortunately without much help from us.

Well, not to put too fine a point on it, Fmpden only warned about traffic on a Sunday afternoon--not a bad thing to do when you are on a limited amount of time.
And if they are total beginners, I joined that it would be a hard day, which I think is also true.
Information can be just that--information. Or opinion based on experience.
I really hope she'll come back and tell us more.

The OP was told to definitely NOT ski.

You win, Whatever.

Do hope this is not your planned weekend for Denver. But you probably will be able to cross country ski down the 16th Street Mall with out having to drive any place.

And to think I made a comment on a different post about sometimes CO not having enough snow before Christmas. Well, this year will not be the case.

Well, sometimes we don't. Headed to Beaver Creek next week. Expectations are high. Need to get the legs in shape for another season. Each years seems a little harder. Trying to decide if I should replace my eight year old skis. When I bought them I thought that would be my last pair.