Looking at your sisters horoscope, her lagan is Aries and rashi is Taurus. Brith nakshatar is Krittika. 7th lord Venus is debilitated in the 6th house which is not good for marriage. Rahu in the 7th house is also not auspicious. Mars in the 7th house makes her mangalik. The horoscope is weak on the marriage front. Marriage will get delayed because of the above position of planets.
Blessings,
Navneet Khanna
Astrologer