Did I buy the wrong pepper plant; I wanted jalapenos, but they're really light green?

I bought a 4 pack of what was labeled jalapenos (over a month ago). I am not an experienced gardner, and I have never grown jalapenos. They are all blooming and growing like crazy, but they are very, very light green. Some are even yellowish. I have yet to pick one because I am wondering if they will darken, but so far they have not. Most of the peppers are still small, about 2 inches, but one of them is about 4-5 inches...and what's weird is it is the one lightest in color. From what I have written, does it seem like I have bought the wrong pepper...or is this normal for jalapenos?