You cannot learn whether you can swim from the edge alone.

Some knowledge only exists on the other side of the attempt. You can study, plan, ask people, and rehearse in your head, and none of it will tell you what happens when you are actually in it. The edge offers preparation, which is useful, and certainty, which it cannot deliver.

When you notice that you have been preparing for a long time, ask whether you are still learning or just delaying. If the former, continue. If the latter, find the smallest way to actually be in the water: a trial, a first session, a single real attempt. The information you want lives only there.