Morty was only 5 weeks old when I took him home - the people we got him from got the dates wrong, I backtracked and worked out how young he really was.
Fortunately he was eating solids and seemed weaned, so feeding him wasn't a problem.
His issue was a bit of urinary incontinence and failure to groom. He'd leave a little wet patch wherever he sat, poor little guy. Fortunately that didn't last too long, just a couple of weeks. Learning to use the litter tray took a couple of goes, but he got it fairly quickly. He also had a bazillion fleas, but a couple of rosemary water baths took care of them.
He never really 'got' the grooming thing till he was about 2 years old, despite having an older cat around for his first 6 months or so, and his slightly older 'brother' who had no problems grooming. It was after the brother died and we adopted Milly, an adult stray, who basically stalked him around for the first few weeks she was home, then held him down and bathed him like a baby. He got it very quickly after that!
Morty is now a happy, healthy affectionate 13 year old.
Would I do it again? Not by choice, but if it was by necessity, yes, for sure. It surely isn't any worse than bring up 4 puppies from newborn, even with their very attentive Mummy around!