The ending presenting itself somewhere around the 15-20% point of the story is a good sign. I don’t need to know all the details of the path to the end, I just need to know enough about what will drive the protagonist forward.
It’s also ok if, at the 25-40% point of the story, the path I thought I was going to take turns out to be the path that I will not take. Basically, anything that coherently moves me forward is nice, sufficient, enough. Nice, sufficient, enough feels way more organic than fervently correct paths.
Likely, this feels this way because this is how I live, and want to live. What makes me feel very certain in a desirable way isn’t knowing “I will do X, then I will do Y, then I will do Z. Then A will happen, so B will happen, so C will happen, therefore, at that point, I can do X1, Y2, and Z3…”
No. What makes me feel like everything is working out is knowing that the end product resulting from X, Y, Z, A, B, C, X1, Y2, Z3 is inevitable.
In my fiction world, that inevitable end product is the protagonist’s happy ending.