Is it normal to not care?

At least text her 3 times a week and that's all good !

Girls are different than guys. It's nice to know that you are thinking about us when we aren't with you. It's nice to get texts from you when we least expect it. I don't think she literally means to ask her what she is doing all of the time, she just wants you to give her more attention and let her know that she is on your mind. I can tell she really loves you, you should be making an effort to text her more, even if it's just once or twice a day. It's not that hard. If it makes her happy and she stops nagging you, it will eventually make you happy too.

Hahaha! I like the way you said, "I know you're going to think I'm naive, but knowing her, she would never cheat on me and she's just trying to make me jealous and it never works."

Funny thing is, you're probably 100% right. If she really were cheating on you, she probably wouldn't be saying, "I could be cheating on you and you wouldn't even know it." Hahaha! Poor girl.

Anyway, its normal. You don't care to text all the time. There's nothing wrong with that. And you even said it yourself, you wanna have something to talk with her about when you guys are actually together in person hanging out. Normal. Now, you just have to explain that to her. If she doesn't understand, thats her problem. There's no reason for two people to be constantly texting each other on the phone every minute of everyday. So for you to feel the way you do, its normal.

She'll grow up some day!

Normal but I guess she just wants to know you're thinking of her.

Of course it is, she sounds a bit on the Fatal Attraction side.