Starting with 1 cat, especially after never having any cats before, is a smart idea. But know that it’s very likely a pathway to 2. 2 will almost always be better than 1, unless you’re just not ready for the idea of dealing with 2 different personalities. Oh, and never declaw a cat. If it already has been, that’s one thing, but expect a lot of aggression, since they only have 2 methods on defense now, instead of 3.
For now, get a single cat from the shelter, tell them about your needs and expectations. Let them know that you, for now, wish to only have 1 cat, and to try to accommodate that. This will get you at least reasonably accustomed to dealing with how cats work; you will be training both the cat and yourself.
Now, maybe you’ll never want more than 1 cat, you never have more than 1 cat, you get solo cats, more elderly, and keep on doing that as they continually die every so often, and maybe that’s the life you live. And that would still be a good thing, because at least those cats would get some love and care, which is better than just not getting any cats at all.
For now, if you really want a cat, just go get a single cat. Take care of the fuzzball, and give it the love it needs. Maybe you’ll change your mind in the future, maybe not. No one knows the future, even yourself. And that’s okay.
Both are definitely bad.