Fingers slip off guitar strings?

I'm beginning to learn how to play guitar. My fingers are skinny and long and i have long finger nails. I would really love to play guitar however my fingers keep slipping from the strings. It mainly happens when i try to hold down multiple strings to make chords. My hands look all awkward and junk and then they goof up once i go to strum the guitar. There's no way i'll be able to play chords fluently let alone a simple song. Please help, i aspire to play guitar. P.s , its an acoustic by Washburn (: