Hi my cat is about 5 to 5 1/2 months old. Yesterday I caught her mating with my 2 male kittens about 51/2 to 6 months old. (I didn't have any intentions on keeping them I was fostering until a home was found. That home just happened to be mine. lol) I was planning on have them all fixed at some point this month. Anyway, I caught them mating yesterday and they have never behaved or showed any signs of being in heat before this. Today they are acting completely normal. Could she possibly be pregnant already or could yesterday just have been a freak incident?