Welcome to BYC! It's great to have you.
A single chicken should only be kept in the situation that you have a lot of time for it and it is kept as an indoor pet. It would need to be diapered, kept inside, treated like a dog or cat and given plenty of attention.
Otherwise, you need at least three birds. A chicken, a buddy, and a backup. I would never have less than three at any time. Before you even think about getting chickens you need a secure coop and run. Are you sure you want to obtain your first flock through hatching eggs? A good incubator is pricey. Eggs are of course unsexed and you will likely end up with at least a few roosters, which you will likely have to either butcher or rehome (and rehoming roosters is not an easy task). If only one chick makes it to hatch, you'll need to try and find buddies of a similar age for it which can be a hassle. If you put too many eggs in you could end up with tom many chicks. Hatch rates vary drastically depending on the incubator, eggs, and other factors. You could set 20 eggs and hatch only 2 chicks or your could set 8 and hatch 7. It's unpredictable, especially for a new keeper. You would be better off purchasing sexed pullets.