I was trying to breed for 4.5 years and no go till this year, you may have the same problem I did, which was I had a female and male but my male was infertile which ment I waisted 4 years. this year I ended up buying myself a proven breeder male and I now have 7 -8 fertile eggs out of 24 eggs left in the incubator.
its not uncommon to buy a pair and it just doesn't happen for a few years which sucks but also really prepares you for when she actually does lay.
has she exspanded in size like looking bloated then a normal feed? you will really notice this if she hasn't eaten for awile. then she'll shed about 2-3 weeks after and then it's rouphly 25 - 30 days after pre lay shed that she'll lay. she'll become more active in and out of the next box, basking more and more. and then she'll stay in her box for a few day's and you won't see her this is a likely time when she is ready to lay any minute. that and you may notice her laying on her back with her belly showing and real loose coils.
if this happens then its a good indicator she is due to lay in a week or 2.
what method are you using for incubation and tub substrate method etc? have you sorted that out yet? or are you going to alow her to incubate them her self and if this is the case is her enclosure ready prepared for her to do it?
once she starts showing signs of belly up and in and out of the box, remove your male from her enclosure. she also won't lay till she feels her nest is perfect and how she wants it. don't be alarmed if she lays more slugs then exspected seeing she is a first timer, and during the incubation period you loose some or most of the clutch, this just happens as long as temps and humidity is kept pretty much at 31.5 -32 degrees during the day and doesn't drop below 29 degrees at night you shouldn't have too much problem.
well hope this helped and good luck