Hello! Congrats on your plans for cat adoption! Here’s a few pieces of advice I have from experience:
Kittens are a lot of work. They’re really cute! But they are babies and they act like it. You have to teach them a lot of things about the world, and how to interact with people/other animals/things. And often most places will only adopt out kittens in pairs, since they benefit from having a buddy growing up. Since kittens are in high demand, they often have a bigger adoption fee, if that matters to you. Adult cats between 2-10 years are probably ideal for most new cat owners as they are well established adults that won’t need a lot of training for the most part (but definitely know as much of your cat’s history when adopting if you can!).
Cat breeds aren’t like dog breeds, by and large. They are mostly common cats of different colors down at the animal shelter, and cat owners will swear up and down that cat colors have personalities (torties are sassy! Orange cats are dumb but sweet!) but it’s largely just the individual cat’s personality. The important things for you are probably going to be fur length (long hair and hairless cats require a lot more maintenance or it’ll effect their health) and how well you get along with the cat individually. The one thing to note is do not adopt a bengal cat as a beginner! They are hybrids with wild cats and act like it! And also I would advise against smooshed nose cats/floppy ear cats/tail-less cats/short legged “dwarf” cats, as they have some pretty bad health issues from those genetic differences.
Cats in the shelter are stressed and probably not going to act exactly the same way when you take them home. If they’re very friendly, they could be more standoffish, or vice versa. You just gotta find the one that speaks to you! And be patient allowing them to adjust when you take them home. Give them a landing space with a litter box, water, and maybe a little food in opposite corners, and give them some hours to get used to the sounds and smells of their new place. Depending on how much space you have, it’ll be between a day and a week for a cat to get settled.
Get the very basics to start and be ready to get more stuff later. A basic litter box, scoop, and a cheap carrier will do it before you adopt. Use your own dishes for water and food before you go buying anything for the cat, you don’t know right away what needs they’ll have. The shelter should recommend you food, get small quantities (not bulk) until you’ve had your first vet check up in case that changes. My cat is spoiled with a much bigger litter box than our first pick, a water fountain, an automatic feeder, wet food on a plate (most cats like flat surfaces instead of bowls for food), and so many toys he doesn’t like anymore!
Have fun! Cats are great. If you learn their body language and respect their autonomy, they’ll love you so much for it.