Did you have the cat scanned* for a microchip at the vet? You must do that!
Just asking if the vet has heard about a missing cat isn't enough due diligence on your part. Why do you assume it was abandoned? You could be taking someone's pet. I picture two little doe-eyed girls between 4 and 7 crying themselves to sleep every night after praying to Jesus that their kitty is okay. They put signs up all over the neighborhood, and Dad took them door-to-door asking after the cat because the little girls insisted, but no one knows anything. They are heartbroken. Please return their cat so Jesus won't have to send you to Hell.
Write back after you do this and we can talk about what to do about your parents.
Thanks
* Not the same thing as a CAT scan, in case you were wondering.
No chip, I had her checked out at the vet's, that's also how I knew she was spayed. He pointed out the scar. I have actually kept an eye out for fliers. I'd go door to door, but campus is really no where near any neighborhoods to know where to start. She was pretty skinny, so I think she had been on the streets for a while. The vet said the owners probably moved and just let her go, he sees it happen all the time around here.
I've had her for about 3 weeks now, and have pretty much figured I'm not going to find her owners. I have tried though. I thought about taking her to the pound or a rescue, but I'm scared she'd be hard to adopt out at her age.
You are a warm-hearted soul to save the cat. As a cat owner for over 30 years, I've both adopted rescue (shelter) cats and took in endangered feral cats over the years (though I've never had more than 2 ever in the house at a time).
Unless your parents are intolerant, afraid of, or allergic to domestic pets, I recommend you just call them in advance and let them know very confidently that you have rescued a cat that was very abandoned and malnourished and are nursing her back to health. Include the "responsibility" details about how you had her evaluated by a vet, researched local rescues for lost pets, and explores renaming options, but you are able to manage the modest costs of her care and have decided to keep her, adding that you are excited to be a responsible pet owner.
This may put them at ease if their first reaction would have been that you had not thought this through and just wanted a pet without considering her care and welfare.
If you haven't been a cat owner before, there re some great books and websites that can educate you on daily feeding, care, play and litter issues as well as behavioral issues. The vet and places which offer medical/grooming services like Petco and Petsmart often has a specialist on staff who can offer advice also. Just make sure not to only trust "a sales persons" input, as he/she may know a store's products but not what is appropriate specifically for your cat.
Maybe you can name her Cary, after our helpful GuySpeak friend!