As Sue pointed out Civil reg did not start until 1877/8 thus except for a very few dissenting families (and very few) who made use of a clause allowing personal registration in an 1849 act that allowed baptisms + marriages in dissenting churches to be legally recognized. Thus your only record is the baptism which generally was within a few days - vicars generally noted the baptism of any older children - a few cases you might find a birth date noted as well but very rare (usually the vicar's own family!) - any side notes in the reg can be found on the mormon film of the official (1911) copy of the parish reg - if you apply (+ pay) general registry (look up on www.gov.im) you can get a certified copy of this this entry but renting the film is half the price and you would probably need it to trace back anyway