Ketu in 1st house in Astrology makes the native stupid, filled with anger, making rash decisions, unless the lord of the sign where Ketu sits is in a good position or aspecting Ketu from a certain house.
The1st house rules body and personality. Most astrologers will say it rules the majority of a person’s life and its luck as well, but it’s not true. The luck, career and wealth factor is ruled by other houses. However, it's the foundation of your life, so a weak foundation will make other planets a little wobbly sitting in a house. But, may people have bad ascendants, but due to other planetary positions they come out quite well.
The first house represents the birth itself, becoming an individual. It represents life overall, the self, and the whole body. Whatever influences the first house will impact the entire life, the personality, the body, and the complexion. Events happening during and shortly after birth also belong to the 1st house. Physically, the 1st house corresponds to the 1st part of our body, the head in general_ and the skull and brain in particular. The correspondence with Mesha (Aries) adds physical mobility and overall strength. You have the Lagna lord in this house; therefore, it is an important house.
Ketu is the south node of the Moon and the rest of the body of Rahu. This is a headless body representing separation, isolation, and the abandonment of the material world. This shadow planet represents spirituality, nothingness, and goals that we already achieved in past lives. In this life, we only rely on those things as a last resort.
Ketu in Vedic Astrology is also an unsteady and sometimes treacherous force, but its qualities are more of an abstract, inward nature than Rahu, who is more concerned with outward, worldly matters. Ketu can bring hindrance and obstacles in the physical realm of life but indicate sparks of intelligence and the mind's brilliance. The above significations are extremely important to know by heart. You should memorize them and use them often to remind yourself of the essential nature of the Grahas.
Note: The degree of auspiciousness and inauspiciousness will depend upon a complete analysis of the horoscope (birth-chart).