it is hard to tell with first timers but this one last year calved on 2/4 this pic was 6 days before. she was making a bag 3 months earlier. and what a bag she had.everybody said she will not go to february. i knew when she was bred.
Notice the sunken-in look betwen the tailhead and the pin bones. Yours is not ready yet, swollen a bit, but I'd keep an eye on her and note the changes day-to-day as she progresses. Could surprise you but watch closely and observe.
Good luck
DMc