The chances that shes not pregnant are slim im afraid to say unless your lucky they have kits so early and your male would be able to make her pregnant at the age he is. Was he showing any sighs of hoping on her whilst they were together. Rabbits are very hit and miss with the temprement and people dont realise when they get them that there harder work than most people realise. I think alot of people just see the cute fluffy bunny and thats it. My mate owns a mini lop fawn colour. Also a french lop doe fawn and shes massive and her feet are gigantic. She is very soft natured and her and the male love each other to bits. I feel its best to have 2 as they keep each other company.