Scorpio does not launch. It incubates. A new moon at 16.89° Scorpio plants something underground, and underground things die when you dig them up to check on them. Your announcement is the digging.
Watch what happens when you describe a plan out loud too early. The plan does not get stronger; it gets replaced by your explanation of it. You start managing how it sounds, who approves, whether the phrasing lands. That is Mercury retrograde work at its worst: ten versions of a message, zero versions of the thing.
The private choice also protects the terms. Venus retrograde at 23.32° Libra is reviewing money, value and agreements, and it sits 0.64° from an exact sextile with Mars in Leo — a cooperative 60° angle, exact to under a degree. That points at effort spent on what you already have: a debt paid down, a draft finished, a rate renegotiated with one person instead of pitched to a crowd.
There is a second reason to stay quiet, and it is the one people resist. Saturn retrograde at 8.81° Aries sets a slow clock. Anything real you begin now gets tested on time you did not choose. Saturn at 8.81° Aries makes patience the price of entry, and keeping the plan private means the test happens in your process, not in front of an audience that already formed an opinion.
So answer the payoff on Mercury retrograde directly: starting is not the mistake. Locking terms in public is. Begin the private version, keep your own notes, and let the first draft be bad where only you can see it.
Then let the Moon's square to Mars do its job. The two bodies sit 84.21° apart on the 90° square, a 5.79° orb — a frictional angle that turns inward reflection into forward motion. Mars direct at 22.68° Leo wants to build something it can point at. Scorpio's new moon wants the foundation poured first. The compromise is a task you can finish today with no witnesses: the transfer made, the module completed, the workout logged before you tell anyone you started.
Refusing to explain is the delivery method here, not secrecy for its own sake. You are not hiding the plan from people who would support it. You are refusing to hand it over before it can survive being handled. For more on why this sign keeps its work under the surface, read Moon in Scorpio: Meaning & Traits.