According to statistics the follow applies:
Only twenty five percent of couples who are actively trying to have a baby will conceive during the first cycle.
Sixty percent of couples fall pregnant within the first six month of attempting to conceive.
Seventy five percent of couples will conceive a child within the nine months of trying to fall pregnant.
Ninety percent of couples who wish to conceive will do so within eighteen months.
I fell pregnant after 6 weeks off the pill, a close friend was trying for 6 months, and another friend has been trying for 2 years and is still not pregnant.........we are all very different!
As long as your GF is having regular periods, and is definitely ovulating, there is no reason to suspect there are any problems at this stage.