Marrying a Manglik girl with strong mangal dosha and Antya nadi dosha, while you’re a non-Manglik, and having low Kundli score (11/36) does raise serious astrological concerns. Mangal Dosha can cause emotional imbalance, aggression, and conflicts, especially when not matched. Antya Nadi Dosha may affect health, and progeny.
However, if love is strong, remedies and conscious efforts can help. Mangal Shanti Puja, Kumbh Vivah (if applicable), and Shiva-Parvati worship are recommended. For Nadi Dosha check Nadi Paad Vedha. So get a proper horoscope matching done.