Connecting with my oldest

I don’t know how to approach this or how to say this but I’ve have a TERRIBLE connection with my oldest daughter due to who her biological dad is and how I ended up finding out about her when I was pregnant . Since she’s been born it’s been so hard . I had an emergency c section so it was even harder . She’s almost five and I really want to re gain that connection with her again . I feel like a bad parent but I’m a trying parent . Advice ?