Fixing a Hole with Body-filler 

First off, I have never done body work before, and I am nowhere near a pro at this. That being said I don't think this turned out horrible. But I am curious how long it will last.
The truck is my new to me 1996 Dodge Dakota Sport. It's a 5 speed, 4x4, lifted, and previous owner swapped in a 5.9l magnum. It is in surprisingly decent condition for living in nys winters. Not perfect, it certainly has its fair bit of rust, but I have seen worse.
I sold my Focus and got this lol yup priorities...