I have the worlds best Bengal cat named Lucy. We recently adopted her and she had not been fixed. The breeder had too many Queens on her hands, so she rehomed her with us. She told us she was possibly pregnant and she is. She is due any day. Her babies are moving a ton. It's really such a neat experience!

I always wanted to have probably three cats. So I thought I would keep one of Lucy's kittens. However, I am really worried that it might be against her instinct and they might not get along. Lucy is such a great cat, I don't want to stress her out at all or change her in any way.

All of my cats I had previously loved their playmates, but I am not sure about Bengals or mama and kittens together. Does anyone have experience with this?

I'm pretty sure that he mothering instinct will kick in and she will be fine with the kittens.

I'm guessing all will go well.

Instinct should see her right.
I recommend getting her thoroughly health checked yourself with your vet and consider insurance to cover all eventualities and costs just in case.
If she is all clear for bugs and bacteria then great, if not its best to prepare and research how to handle any infections after birthing (to protect kittens) ... im not sure what if any meds can be administered during pregnancy.

I think you should get ready for anything and while Im sure you had a lovely chat and plenty of smiles with this ''Breeder'' you should be wary of her and the care she gives her cats.
No responsible breeder would hand over a pregnant queen like this to a customer (another breeder or close relative with experience maybe)... if she had to many queens she could have given you one of the queens not currently pregnant as a discounted pet with agreement that you spay.

After this girl has had her litter you should spay her and allow her to live as a happy content family pet.
I hope everything works out happily for you, your girl and the new kittens.
Research research research