You are mixing two different schools of astrology. By Vedic your Sun can be in Pisces and by Western, it will be in Aries. This is due to ayanamsa, which is taken into consideration when they calculate the vedic charts.
Ayanamsa (ayanāṃśa: from Sanskrit ayana ‘movement’, and aṃśa ‘component’), also ayanabhāga (from Sanskrit bhāga ‘portion’), is the Sanskrit term for many systems used in Hindu astrology to account for the precession of equinoxes.
Blessings,
Navneet Khanna
Astrologer