I'd say the cause and effect is a little backwards there... she's not good at them because her exposure is low, and her exposure is low because she's really not interested in them.
My daughter made learning letters/shapes/colors/numbers look easy, but we turned it into games, so it never really seemed like a big deal to us. For instance, I'd play a game with her during bath time where she'd be surrounded by tub toys and I'd say, "Show me something purple." When she got to the point where she'd pick up something orange and hold it up with a silly grin on her face, we knew she had it, and she was ready to move onto something new.
Where she really showed her difference was when she'd ask a deeper question, we'd answer the question, and it just wasn't enough... she wanted MORE. My wife used to punt the tough ones to me, so I'd come home and get something like, "What happens to food when you eat it?" So I'd sit her down with me at the computer and pull up images of the digestive system, point out the different parts, and give her a brief description of what each part does. Several times over the next few weeks she'd come back to the same question, and I'd sit her down again and go over the material again. I'm pretty sure she was just trying to get everything out of me she could, and once I stopped saying anything new about it, she moved on.
So there she is for a checkup at three years old, she spots a poster in the doctor's office, and says, "Look, Mom! Small intestine, large intestine, ppppbbblllttt!" And the doctor just looks at them both. That's the gifted child difference in a nutshell.
You never knew what was going to fire her curiosity. One time she was upset about all the rules and complained about how we could do anything we wanted, and I mentioned jail. I can't tell you how weird it is to be spending time with a 3yo who can't seem to get enough of staring at pictures of prison cells.
