I'm thankful for all the replies!

Before I started this thread I was 99.9% going to get a kitten in a few years... but now (after reading the replies) there is literally ZERO chance I will get a kitten when I have birds. I would never be able to live with myself if my birds got injured or worse just because I wanted a cat!
Having to keep cat in separate room from my birds is definitely NOT something I would ever want to sign up for. I hope my birds live a long time... but when they pass is the only time I will ever get a kitten.
I've wanted to adopt a Mustache Parakeet for the looooongest time but I was too worried the Mustache Parakeet might injure my tiels (they'd never be kept in same cage of course). I also have to make a decision whether I want to switch from being a bird person to a cat person!! I consider myself a bird person.... I love the way birds smell and am addicted to sniffing them!! Why do they have to smell so good LOL.
... I've had cockatiels my entire life (while having small dogs many years ago)... and I did have a cat when I was a kid. I will never have a dog again as I'm not huge into dogs.
.... but I think it would be a nice break/switch to become a "cat person" as birds are not the easiest to care for and I fell in love with cats after I was hanging around a cat that stays at an avian bird store of all places. My old neighbor's cat was so amazing and they had a DIY realistic cat tree... it was really cool.
I have many years to make my decision (if I want to switch to being a cat person) as my cockatiels are only 9yrs old and 4yrs old. I THINK I can make the switch from birds to cats.... but I'm not 100% sure. I've got plenty of time to decide... in the meantime I will enjoy my birds with NO cats!!