Answer: The Sun will actually be in the Pisces constellation
Explanation: There's roughly about a month difference in the astrology date and the true date of constellations which the Sun is in. This is due to the fact that the earth spins like a top on its axis because it is inclined by 23.45 degrees. This phenomenon is called Precession.
This consequently causes a difference in the positions of the constellation, that is, from its astrological position and its true position because of the shift caused by the earth's precession.
Therefore though the constellation Aries are March 21 to April 20, the actually constellation the sun is will be Pisces which are March 12 to April 18