The world will not end if you tell your cat 'no'.
Letting cats have their own way in everything is a tradition that goes back at least to the Prophet Mohammed, who cut off his sleeve rather than pull it out from under a sleeping cat. I constantly hear other cat owners talking about how their pet keeps them awake all night wanting to be played with - and they oblige, or (prise entry) 'when kitty puts his fat belly smack down on your face. Happened to me last night and the last thing I remember was thinking “I’ll never be able to go to sleep now.” '. This without a trace of irony.
You wouldn't catch me doing any of that! I adore my cat, but I refuse to be owned by her. Not that I can say she's my pet: we're housemates, and equals.
You wouldn't expect one of your friends to cater to your every whim, and you'd be unlikely to stay friends with someone who treated you that way. Your cat is quite capable of knowing what she can get away with, and who will let her get away with it. It is perfectly possible to have boundaries in your relationship with your cat.
Two pearls in one day: aren't you lucky to have so much wisdom on tap.