If she ovulated and had her pre-lay a month ago it should be a matter of days.

Pick her up holding her tail up and head down then rotate her so she is tail down and head up you will be able to see how far the first egg is from the vent area.

If you do not see any eggs than this you were wrong about the ovy

Snake ovulate than typically have a pre-lay shed 14 days after that and lay eggs 30 days after the pre-lay shed, however I have females laying 40 to 50 day POS