Carry on. You are much earlier than the advice you are reading is aimed at, and the advice has been flattened in the retelling.
The original point was never "stop as soon as it works". It was that unscalable work is how you learn what to say, and you graduate when you have learned it — not on a schedule. At eleven customers you have not learned it yet. You have eleven data points, several of which are probably not the same kind of customer.
The honest signal to move is not a customer count, it is one of these:
- You physically cannot keep up, and demand is being lost because of it
- The emails stop working, meaning your reply rate falls as you exhaust the obvious people
- You notice you are writing the same email with the names changed
That third one is the real graduation, and it is worth waiting for, because it hands you the scalable version for free. When twenty personal emails have converged into one argument, that argument is your landing page, your posts and your ads. Trying to write those before convergence is exactly why your scalable attempts returned zero — you were guessing at a message you had not found yet.
So the answer to "is it a trap": no, but stopping too early is. The trap is building a channel for a message you cannot yet state.