I agree with letting them choose you. Our boy was chosen for us and while we love him dearly i often wonder if he was meant for another family. Our girl on the other hand chose us without a doubt and is def meant to be part of our family.

You can get healthy kittens desexed at around 14 weeks. I got mine done then. It was very easy and recovery was very quick. I did my research and found that in healthy kittens it has no adverse affects on them. Plus you can definitely avoid any behaviours that come from early sexual maturity. If your kitten is underweight or a bit sickly though it is better to wait.