Two different questions
'What's your sign?' hides two questions. Western popular astrology asks where the SUN was on your birthday, measured against the tropical zodiac. Jyotish asks where the MOON was at your birth moment, measured against the sidereal zodiac. Different luminary, different reference frame — so the answers often differ, and neither is a mistake.
Your rashi (janma rashi / chandra rashi) is the sign the Moon occupied at birth. In Vedic practice it — not the sun sign — anchors daily predictions, dasha interpretation, matching, and the nakshatra system layered beneath it.
The ayanamsa: why the zodiacs disagree
The tropical zodiac fixes 0° Aries to the spring equinox; the sidereal zodiac fixes it near the actual stars of Aries. Because Earth's axis precesses, the equinox drifts backwards through the constellations about 1° every 72 years. The accumulated gap — the ayanamsa — is currently about 24°, using the Lahiri value standard in India.
Practical effect: someone born a 'Taurus sun' in the Western system frequently has a sidereal Sun in Aries, because subtracting ~24° often crosses a sign boundary. The same shift applies to every planet, which is why a Vedic chart can look one sign 'earlier' than a Western one.
Why Jyotish privileges the Moon
The Moon in Jyotish is manas — the mind, moods, and instinctive responses; the classical texts read general life experience from the Moon as an alternate ascendant (Chandra lagna). It also changes sign every ~2.25 days, making it personal in a way a month-long sun sign cannot be, and it selects your nakshatra, which starts your Vimshottari dasha clock.
The Sun still matters in Vedic astrology — soul, vitality, father, authority — it simply isn't the default lens for daily life the way popular Western columns use it.
So which horoscope should you read?
For Vedic daily/weekly forecasts (including MyAstro360's), read your MOON sign — that's what the predictions are computed against. If you don't know it, any free kundli reveals it in seconds from your birth date, time and place; without a birth time it can still be determined on most dates, since the Moon holds a sign for over two days.
Reading both your rashi and your Western sun sign is fine — just know they answer different questions, and don't be surprised when they diverge: with a ~24° offset, roughly two people in three have a sidereal Sun one sign behind their tropical one.