My 15 week kitten is dying to go outside. She has had all her jabs and she' been outside but on a harness so she won't run off. We are installing our cat flap in the next few weeks but I am so scared that she won't come back as she is a Bengal cat and costs a fair bit.How do you know that they won't run away? I just need some advice on how to make sure she will come back. Thanks