I am the founding engineer at a startup. Since the beginning of the company I've reported directly to the CEO and then the CTO after he was hired. Our company has grown considerably since then (from three employees to 100 employees).
A while ago we hired a manager specifically for the engineering team that I am on. All of our junior engineers and engineers hired since then have been put under him. Lately, our CTO has been talking to me about moving me under the manager. He tells me that it's just because he doesn't have time for me to continue being his direct report, which I don't necessarily doubt since he's a busy person these days. However, this concerns me because our manager is more junior of an engineer than I am and I don't feel that I have as much to learn from him as I do our CTO. Also, I'm honestly insecure about seemingly being moved down the chain at a company I've been at since the very beginning.
I suppose I need to talk more about exactly what this move would mean and what it would mean for my standing in the company. How should I be thinking about this? Is this certainly a negative for me or is it possible for a re-org such as this to be a positive move? If the latter, how can I make the most of it and make the transition as smooth as possible for all involved?