Kidnapped a stray, turns out she is pregnant...

Hello cat lovers, Two days ago I was having a few Saturday night beers at my local bar and a small stray kitten and very cuddly kitten found us. Considering there was a big storm coming and I was debating getting a second cat we kidnapped her and took her home. This afternoon I took her to the vet to make sure she is healthy and to see if she was chipped and maybe has an owner. Unfortunately no chip.

Turns out it's not a kitten but an adult cat - around a year old she is just small. And to my surprise she is currently pregnant with 3 kittens. We'll as I am not able to support five cats and I am certain that won't be able to find new homes for the kittens the vet suggested to spay/abort. While this seems like the most reasonable option and we agreed to get it done, I still have some doubts if it's not gonna affect her mentally or physically in the future.

Is this a safe procedure? Will she hate me for the rest of her life for this?