Horsefield egg. Fertile or not.

[Devillady77]

Hi, I'm hoping someone can help me, my horsefield tortoise laid her first and seems to be only egg on 14/3/17, it doesn't seem to be doing an awful lot, I'm assuming it is possibly infertile, what should I be looking for, it is still pinkish in colour and has a bubble inside but has no veins or black areas which I've read there should be by now.
Could someone give me some advice as this is my first time. The egg is being incubated at around 30 degrees.
Will welcome any advice.