1. Don't move into management because of any external pressure because you "ought to". Also don't do it just because you are tired of writing code. Do it when you feel like you have more to offer by building and leading teams and delivering through your people than with your individual delivery. Ideally, get a chance to try it on an interim basis at a company you already have trust in. There is a LOT of stuff about management that is invisible - it's not just telling your reports what to do. Managing upwards is a terrible irritating part of the job, and you can easily become the manager you yourself would hate if you are not careful.

2. I think career progression and satisfaction is all about balancing and trading off playing to your strengths, then focusing on your weaknesses.

If you only play to your strengths, you won't grow in breadth enough. You can become a top subject matter expert, but your utility will be limited to that domain.

If you only focus on your weaknesses, you will become well rounded, but not good at anything, and you won't stand out from the pack in any way.

Only you know which of these two you more need today. Good luck with the decision :)

3. Someone else already mentioned - it's not your job to determine if you are qualified for a position. The company hiring you is. If the work is interesting to you, and they're making you an offer, and you didn't lie - then you are qualified. Learning and stretching yourself would be part of the job.

4. Nothing I say above will fix a foundational anxiety like "what if i'm not good enough and get fired". What helps me with this class of extreme worry is to consider the worst case scenario, visualize it, and recognize that ultimately it's not that bad.

So what if you get fired? Again, assuming you didn't misrepresent yourself, the company would be just as guilty of the mismatch in fit as you. You won't be blacklisted. They might even be willing to give you a referral. But if not, you got 3 offers once. You can get 3 offers again after you get fired. The worst case scenario isn't that awful.