Hello
Are you absolutely certainyou want to breed them?
It will require a lot of your time to care for the babies and a huge amount of food, too.
Your Jackson's will probably have 1 set of babies 6 to 9 moths after she has been bred and then another set of babies 6 to 9 moths after that.
Jackson's babies also have a very unfortunate tendency to suddenly and unexpectedly drop dead before they reach about 6 months of age.
No one knows why that happens and not everyone's Jackson's babies experience this but you are better off being aware that it can happen.
My captive bred Jackson's xanth females, even from the same parents, vary in size and weight.
Perhaps your T.j. xanth is not really a xanth.
The other types of Jackson's are smaller than xanths are.
Of course if she is a xanth then she just might be a small girl or she may be a runt.
If I am not mistaken Jackson's xanths are not often found in Europe and the more usual type of Jackson's there is the Trioceros jacksonii jacksonii---which are a smaller type of Jackson's than T.J. xanths are.
Here is one older article with some pictures of the 3 types of Jackson's
http://www.chameleonnews.com/10JulManchen.html