One of the dangers of internet genealogy is that there is so much information available, and if you don't know the dangers you can build a family tree which is full of errors. Things get difficult with non-conformists before 1837, while parish registers often have large gaps at the time of the Civil War. The problem may be that there are no relevant birth records for your ancestor - and a common mistake is to select the record of someone with the "right name" who is actually the "wrong body".
In answering questions on this site I don't want to waste time answering questions where it appears that the basis of the question is unreliable. In ADAM or MADAM, Harpenden, 17th century I explain why I feel that a baptism that took place in 1652 is very likely the wrong one - and also supply pages which everyone should read if they are to avoid similar difficulties in future.