Not that this will be helpful advice at all, but fwiw, my kids were like that about a lot of things when they were 3-4 years old - they'd be really into one type of new learning thing for awhile, we'd get excited about it and they would move on to something else. In some ways I can't help but think that it's the first developmental stage where they are focusing on how to completely confuse their parents
I wouldn't worry about the reading too much - it will come in time! I also don't know that I'd be for certain she's "reading" the Cheddar's sign - my kids all knew how to "read" the restaurant signs long before they could actually read - they knew the names from having been there before, and the signs usually have distinctive logos.
polarbear
