Suddenly afraid of training

I would start by working on the fear itself. You seem to really know what you want and already have a good rationale. This is what will carry you through the whole process. This basis may need solidifying, and maybe a clear act of commitment (e.g. setting some clear objectives, maybe time-based). Once you’ve set the objective, you don’t take decisions anymore until you’re there, and accept the fear as something to live with. Don’t rely too much on the opinion of others to reassure you (“you should go ahead with it or not” etc.).

Fear also gets much easier once you start acquiring competence (“people fear what they don’t understand”). It can come back when you’re facing stressful situations but then you improve and regain (cautious) confidence.

I had a period of serious doubts a few months ago. Obstacles were piling up, I wasn’t having as much fun flying, and started thinking that it was not for me (I have far more useful and recognized skills which are a better match for me). I was also doubting my ability to maintain good flying competence without constant training.
Then I told myself that the time was not right to make a decision, that I would be happy later to have gone through with it, even if I stopped completely. But I could NOT on a hunch abandon such a long-term objective. I took steps to improve (and did), and now I can’t wait to plan my next flights and use my (2-week old) PPL.

Volaris wrote:

by the fact that I am aware of this and am currently in the process of deciding whether I trust myself to do this

You don’t have to trust yourself. Find a good instructor and trust them to evaluate you. They are trained for this.

Volaris wrote:

But how do I bridge the gap between flying without an instructor and really knowing everything I need to know?
My assumption is that there is a window in which I am allowed to fly alone, but that I would not have every situation under control and might do something stupid, e.g. instinctively pull instead of push or spin due to a wrong reaction.

In my opinion it’s really too early to assess this if you’ve barely started training. You’ll know when you’ll fly and encounter actual obstacles. If anything, it’s indicative of exactly the right mindset to avoid bad things: fear and doubt yourself → improve, control, and limit yourself.

Congrats @maxbc

Volaris wrote:

and might do something stupid, e.g. instinctively pull instead of push or spin due to a wrong reaction.

That’s the main reason people crash. There’s no escape from it. I remember when I got my PPL, there was an Air Force display pilot that augered that way. He was training, flying inverted above the runway at 15 feet or so in his F-5. Then he should pull out inverted (push the stick). Instead he pulled, and smack. At the blink of an eye.

Those guys have been tested and picked and trained for the purpose of not doing stupid things. There’s no escape. Sometimes the brain have a mind on it’s own. How often have we read in crash investigation reports that the PIC was one of the most experienced in the area, with 1000s of hours, highly regarded, and ends up dead due to some odd unexplainable thing ? It must be every other deadly accident or something.

Those thing happen much more often in reality I’m sure. It’s more that we have margins, so even if it happens, we usually have time to recover from it. It becomes just a stupid little mistake, instead of a stupid and deadly little mistake. Procedures also help I think, perhaps a lot.

I’d advise not even thinking about AF447. If you get to fly an airliner you’ll certainly should know how to avoid stalling or spinning at a base level

PS I think you’ll find that tunnel vision played more of role in AF447 than instinct to pull instead of push.
If you have a simulator you can try it for yourself. Here is the scenario "It is pitch black, ice blocks the pitot and the heater cannot clear it. This means that as you climb your air speed increases autopilot switches off due to turbulence from the approaching line of CBs which you are trying to get above
Their tops stretching way above you and can occasionally be picked out in the lighting strikes. That’s where the instinct might be to pull to keep to pre briefed climb speed. But its tunnel vision which makes you ignore other clues that you are nearing a stall and even in one. That’s where training comes in and other factors played a role in AF447.

Volaris wrote:

I think AF447 was similar with instinctive pulling besides all warning signs.

Not so much instinctive as learned. The pilots were trained to rely on the alpha protection, which wasn’t available as the aircraft was in alternate law.

Volaris wrote:

Did any of you also have such thoughts during your training or did you get through it without any doubts?

I think the age that you start makes a big difference. I learnt to ski so young that I can’t remember when it was. When I ski now, I don’t have fear in situations that I think I would find scary if I were learning now. When I am learning something new now that I find potentially scary, I remind myself of the feeling I have skiing, and realise that I potentially can get to a level of competence and confidence similar to what I have skiing. I might not have the confidence yet, but I have the belief that it can be achieved. Perhaps you have non-flying experiences you can tap into as well to help you believe that you will be able to overcome the fear.

Volaris – can you identify any specific reason for worrying? Was it the poor condition of the school plane, for example? I used to worry about that but would say to myself “well it has not disintegrated on any of the many recent flights so it probably won’t on mine”

Fixed wing flying is actually pretty safe. 1st thing is to make sure you have enough fuel; instructors often cut it really close because they know just how close they can go, on their generally very short flights.