Don’t know how I feel about this one. Moon phases at birth weren’t traditionally used for relationship compatibility - that’s a modern development, not ancient astrology, and since twin flames meet in the 3D over multiple lifetimes, you could have different compatibilities according to that each time around.
I would say (like most other external factors), use it for guidance and not confirmation.
Astrologers focus on moon signs, moon house placements, and aspects between charts. The phase thing went viral recently, but it doesn’t have the historical backing that other synastry techniques do. Not saying you shouldn’t consider it… just be cautious with how much you rely on it.
That said, the waning crescent itself carries real spiritual weight across many traditions. It’s the phase of mystics, seers, people who feel like they don’t quite belong in the everyday world. Dane Rudhyar, who developed the modern moon phase personality system in the 1940s, described it as the phase of release and seed preparation. The person embodies the distilled wisdom of the previous cycle.
Being born close together temporally does suggest something beyond coincidence in esoteric teachings. You’re riding the same cosmic wave, dealing with similar karmic themes. Whether that makes someone your twin flame depends more on the actual dynamics of the relationship than any chart marker.
The real question isn’t whether the phases match but whether the connection supports both of your growth. Spiritual indicators can validate what you feel, but they shouldn’t override your actual lived experience. If this person mirrors your deepest patterns and catalyzes transformation, that matters more than any lunar timing.