Regarding the job recruitment

Hi..I am confused about the difficulty which arose in my career. My father who hails from a small village in karnataka studied upto 10th standard in 1970-80's. By birth his caste falls in category-1. But that time there was a rumour among the people in that village that, he can claim his category in koli-dhor, which falls in ST. He got this koli-dhor certificate also. Based on this new category he was able to get a govt job (typist). Later for our admission into the school, he enrolled us under General quota, but caste he mentioned as koli-dhor (the reason for this is his job was under koli-dhor). Throughout my education career, everything I applied in general quota- all admissions, entrance exams etc. I was unaware all of these caste information and moreover i was ignoring all these (in fact not understanding all these) as i believed only hard work should decide the person's ability but not the caste. When my age crossed 22 years, i applied for my caste certificate. This time i was able to get my actual caste certificate which comes in category-1 from Tahsildar. (My father is telling that, the government is not at all issuing Koli-dhor certificate, as this caste is no more in my district). Now i applied for one govt job and have been selected under category-1 for which I have the category-1 certificate and by birth also I belongs to that. But variation is coming with my school records. Even if i am able to get this job in category-1, whether is it right? Is it Dharma or Adharma? Now my father got retired from his job and he is getting pension also. What my father says is, "i was not that much educated, so was not knowing what is right and what is wrong..in a very backward village, from a very poor family, with only 10th class pass, i was able to get typist govt job by taking this ST certificate, even though knowing that i belongs to category-1. As i didn't wanted to lose my job, so i wrote your caste is Koli-dhor during your school admission but at the same time as i was knowing-any way i did a mistake, so let my children should not be a part of this." So always he made us to apply in general quota till his retirement. Now he got retired. I was able to get my category-1 certificate and i got selected for a job under category-1. Now i want proper suggestion, whether i should take this job or not? Even if i take, lifelong i will be thinking i took opportunity of another candidate who got bit less marks than me. What should i do? If i think, whatever i am doing is wrong, then lifelong i suppose not to avail any reservation in both category-1 as well as in ST.