I'll just wait and see what happens. If you like. But as you've already said, if those scientists and philosophers are right, you haven't really made a decision at all. You only think you have. You said the philosophers used to think this way.
Nobody believes in determinism any more.
This is an area of philosophy which has been very much influenced by experimental science. Scientists have found that the world just doesn't work in a deterministic way. Unfortunately, you'll find that the scientific discoveries don't help much on the question of whether you are really free to make decisions after thinking about things. But you might be reassured to learn that the world does not operate like a complicated clock. Everything must be caused by something.