My cat died today- will she be in heaven now?

First of all, I am so very sorry for your loss. 🙁 Yes, your kitty is in the most beautiful place. When I talk to animals on the other side, they describe the feeling as one of complete love, peace, comfort and beauty.
But heaven is not a far away place. You gave rainbow-brightyour cat heaven on earth by the wonderful life and love you gave her. And when a soul leaves a body, it’s simply a matter of that soul, that spirit, no longer being confided by the physical clothing that ties them to this physical world. As one cat showed me, he unzipped his body and stood next to his mom as an etherial mass and said, “I’m right here, mom. I haven’t gone anywhere.”
 Everything has a vibration. The chairs we sit on (very low and dense), us and animals, higher and more malleable, and spirit, which vibrates so high, we can no longer see them. It doesn’t mean they’ve gone anywhere, it just means we can no longer see them wearing their physical clothing. They exist in another dimension, a heavenly dimension, that is right here next to us.
Your kitty hears you when you talk to her, feels you when you hug a stuffed animal thinking of her, hears you when you write to her in a journal. Your kitty will send you signs to show you she is there and loves you. To recognize them, just have faith that she is there and will always be. S/he can now help you as your spirit guide, from the other side.
Is your kitty in heaven? Yes. Heaven is a place of love. You gave her that love, that love never died. She had her heaven on earth with you, she lives in heaven, in the warmth of your love and memories, now, on the other side of the veil, sending the same back to you, and grateful for the wonderful life you gave her.
Here is a post that I hope with help with your process: 12 Things You Can Do After Your Pet Passes
So many blessings to you.  Amama.

Lisa Larson is an animal communicator and reiki master. You can find her at https://pawstalk.net.