We got a 2 year old cat from the cat rescue. She spent the first week in our house hiding behind the photographs on our bookshelf. DH, DS and I just got her used to us by sitting on the floor in the room reading the newspaper or a book. We didn't touch her, left her in the room but we were in and out as it's off our kitchen so couldn't be avoided. Left her food down, which she ate but never in front of us. We spoke to her all the time so she got used to our voices, but just carried on like she wasn't there.
After a week she popped her head around the door of the living room but as soon as we looked at her she was back behind the photographs.
Two weeks later she came and sat by my side on the floor and accepted a stroke.
Now, three years later, she loves having a stroke on her tummy and it's a nightly ritual that lasts well over an hour that I stroke her ears and tummy.
She's never allowed us to lift her - apart from vet visits but it has to be at arms length or she's off. She won't sit on our laps or even on the sofa - we have to sit on the floor with her.
But that's her way. We want her in our lives so we accept her ways, we can understand and adapt, she can't.
But I would get back in touch with the cat rescue for advice if you think it's a bad fit. My first two cats were sisters and only 10 weeks old when we got them. We knew they were feral - they'd been seen out on their own when they could have only been 6 weeks old.
One settled and was with us until she died aged 9 years old. The other used to attack me, my ex (had some sense that cat!) and her sister. We got back in touch with the cat protection league after two weeks and they came to get her. She was re-housed on a farm where she was fed, housed in a barn but not put into the house. She couldn't cope with being in a home with people and noise etc., Apparently she settled very well on the farm - she just wanted regular food, a roof over her head but not the companionship of humans. She became an excellent mouser so the farmer was happy.
Even her sister, the one we kept, spent the first winter sleeping in the shed in really heavy snow. She'd eat her dinner, have a cuddle then go out of the cat flap and we'd find her sleeping curled up in the shed. So we put her cat basket out there with blankets and that's where she stayed. Within a year she'd figured out that the house was a lot more comfortable in the winter and you couldn't get anywhere near the fire from then on!
Not every cat suits a house environment and some that eventually do, need a lot of time to get out of the feral mentality.