I've been reading a lot about heavy lifting and decided to give it a try. However, my muscles are not sore. Does that mean that I am not lifting enough? Is this normal? I wasn't into lifting at all before.

I using enough weights that I am only able to lift about 6 times before I need to stop.

How soon after lifting are you making this observation? Check back in a day or two...the D in DOMS is "Delayed."

I've just started a weightlifting program, and am by no means an expert, but when I was doing research I found that you should try and lift just enough to be able to do 12 reps. I wonder if because you are lifting too much you are unable to do as many reps and therefore aren't getting as much of a workout.

As I was writing that, it doesn't make much sense to me, but maybe someone with more knowledge can confirm or deny my ridiculous claim!

This is day 3 after starting. Should i be feeling sore?

What is your routine like? How many sets are you doing?

If you feel soreness, you'll generally feel it within the next day or even the day after.

Im doing 2 sets lifting 6-8 times. Doing things like bench press and bicep curls.

Something you have to watch out for is something called form. I have had a personal trainer help me with having proper form. For example, say you are doing standing bicep curls with a 30 lb bar. The wrong way to do it is to swing and use your back to lift it. Another wrong way is to use your wrists to lift the bar. And yet another wrong way is to bring the bar so it only makes your arms 90 degrees instead of bringing the bar all the way to your chest. The proper way to do standing bicep curls is to have your feet shoulder width apart and should not bend your wrists and raise the bar to your chest and back down again, each movement taking a full second. You can Google a website or look at youtube videos to find proper forms with weight lifting. Find a weight that you can do the proper form for it and you should be on your way to feeling sore

Not every workout always has to make you sore to be effective. Having said that, if you haven't lifted anything heavier than a gallon of milk in awhile, you should be sore from an effective workout. I'm guessing you're not working muscles sufficiently to fatigue with only 6 reps for 2 sets. Move up to at least 10 reps per set, and do at least 2 different exercises for each body area you work on that day. So for example, if you're going to work on legs that day, do 2 sets up 10 squats, and 2 sets of weighted lunges (10 on each leg). Many of us on this forum really like the New Rules of Lifting for Women (NRLW), and that book does a terrific job of laying out a progressive program that works. Good luck and stick with it!

http://www.youtube.com/watch?v=DkMUxuopjK4

Hoping I can post this link. I like his stuff. He has stuff for women only, too.

When I started a few weeks ago mine didn't hurt the first day, but the next day or two after that I sure was sore.

If you're just starting lifting you should spend a few weeks to a month developing you're stabilizer muscles and your neuromuscular ability, you're bodies ability to talk to itself. It's one of the best ways to burn calories and you'll love the progress. It also reduces you're chance of injury and allows to lift later the full amount you're body can handle.
I mean 1-3 sets of 15 reps covering the whole body in 5-6 different exercises or body parts. Alternate the top of your body with the lower part of your body to keep the blood pumping hard for a stronger heart also. Chest legs shoulder legs back and then biceps and triceps optional.
Do slow reps. 4-2-1 tempo. One second to raise the weight, 2 seconds to hold it there, then 4 seconds to lower it.
The muscle gets sore for several reasons. A new movement or eccentric movements are the most common in beginners. I find if I get a good nights sleep one or two days then I get sore. My body needs rest, lots of it to recover properly.
Good luck.