Help Marshmallow Fight Her Tumor

I write this with a very heavy heart, my kitty Marshmallow is sick & I'm not sure how much longer she has to live. She has a tumor on the underside of her tongue, making it very hard for her to eat, drink, & bathe herself. She's a little bit older, about 15-16 & I've had her nearly half my life. She means so much to me because she's more than just a cat. She's my baby, my support system, my family, & my best friend. I can't imagine my life without her. My heart has been breaking coming to terms with the fact that I know she can't live forever. I just want to make sure she has comfort & happiness for her remaining time. I'm raising money for vet bills, mainly for a biopsy procedure to see what form of cancer & what stage the tumor is in. & Hopefully the doctor can determine how much longer she has with that information. Anything helps for donations, I really wish there was just a cure & she wouldn't have to go through this during her lifetime I would never wish this pain on my worst enemy. Thank you for reading, please keep my fur baby in your thoughts & prayers.