An Experience of Subject change in civil services

Personal experience of subject change--- I started psir 1st week of may n took it because of 1.sheer interest 2. Public admin background a good convergence 3. A good, reliable, solid, dependable notes of subhra mam...i recall I spent around 60% n even upto 70% time on option from may to mid Dec...so, it was really very demanding n even swing of mood in between abt I shuld have continued pub ad or better geography... N it really took space of gs prep or essay writing I desired to write....only thing was interest which kept me on toe n a crash course of mam filled the gap of self study....so, self-belief is important...marking should not be  only reason of temptation...i see on forumias geography result is not as per last yr as it was even visible in our friend circle....but I believe only ur calculation will work in terms of ur decision, self-belief is important, people r clearing in maiden attempt in ny optional, last tym geog mark was 300+ n average very high...n this year pub ad was easier than all years in recent 4-5yrs....n last tym pub ad1 the most difficult even solving 170+ was impossible in good sense but ppl got 170marks in Absolute term in this paper....so a lot of uncertainties but self-belief/confidence I chosen subject with a reasonable calculation ll work...i discussed yesterday with amrita abt her zoology option it seems to be good decision but she knows better about her interest n mark fetching capability of the subject....