What age to introduce a cat flap?

I'm curious what age you can start to introduce a cat flap. I would love to keep the litterbox in the garage, but need to put in a cat flap in the door. Sweetie is about 14 weeks old right now.

Thanks!
Kelley H.

You could start trying now. Have one cat box in the garage and one in the house untill your cat starts using the cat flap and litterbox out in the garage. You do mean the cat flap will just let your cat go into the garage? Right, not outside also? Your kitten maybe abit to young to get the hang of the cat flap yet.But you can start trying to teach her.

You could start trying now, counting on her curiosity to help with the training, but one caution: the long term success of a cat flap depends on how comfortable it is for the cat to use, and that depends to some extent on how high it is off the ground. So, what will be comfortable for her now might well be too low when she's all grown up. If you have the option of reinstalling at a different height later that might not be a problem, but if you have to choose a height now and live with it, it will be a bit of a challenge getting it low enough not to frustrate her now, without being too low for her later.