Should i acknowledge her birthday or drop her altogether?

my niece. she's 28 today. ever since she's become an "adult" her & i havent been getting along. i'm 44. i've always given her any & everything she's asked for. i've always been her friend. i went thru a rough period in my life due to a relationsihp & lost alot in the process, wasnt doing too well. she seemed like she turned off from me. a fight broke out with her & i once & she pulled a knife out on me, my mom's finger got cut in the process (bcz my mom grabbed her arm to keep her from cutting or stabbing me). i tried to make peace with her back then (even though i shouldnt have) but she slam the phone in my ear. eventually we were ok but as years went by she'd give me & others attitude sometimes & she'd act funny - but she'd always ask to borrow money. she even gets funny with my mom (her grandmom) & my mom has done EVERYTHING for her. my niece has never even acknowledged my birthday with a card, phone call, gift, nothing. but every birthday of hers i acknowledge with whatever i can, even if its just a phone call. the last time i spoke to her she gave me attitude just bcz i didnt return her phone call till 2 days lata, i got fed up with her & told her to kiss my azz. she acts like people owe her something. its her birthday today & i was thinking of trying to make peace AGAIN by giving her a card & gift but something in me said WHY SHOULD I???? she never takes initiative to make peace with me. i feel as if i've done nothing wrong to her, why should i kiss her a*s & try to remain on her good side when she doesnt seem to care about me or MY feelings?? i feel like i should put her out of my mind & drop her out of MY life. hell, let HER come to ME for a change or just forget about her. its not like i need her. am i right?