That last egg is a very nice egg to be sure.
You pullet is just starting to get all her egg producing functions working properly. It is not unusual for a young pullet to produce a wide variety of "problem" eggs as she begins to lay. For example, I and many others have found eggs without a shell. This can happen when there is not enough calcium for them (oyster shell for example) but it is fairly common for first-time layers as well.
Also, the egg coloration can vary when they start laying. You might find lots of "speckles" and even "blotches" until things smooth out. Double-yokers are common in early layers.
It looks like she's coming along real well and you have a keeper there now.
God Bless,
