As a person who has had many cats in my life, I am of the opinion that two cats is the best number of cats. If you can afford to care for and have space for a second cat, I’d say go for it.
If you’re not really experienced with cats, be aware that cats almost never get along immediately. It can take weeks of them seeming to hate each other before they become friendly. It’s helpful to put the new cat in a cage where the current cat can see and smell them, but can’t reach them with claws. That gives them a little space to get to know each other before the current cat feels like its territory is being invaded.