You need to look at Meshaw Parish Registers either on microfiche in one of the Devon RO's,at Devon FHS Tree House on Findmypast .

If you don't have a subscription to Findmypast you can access the site for free at Devon FHS Tree House also in many Libraries, Archives and all LDS Centres.

You could try looking on FamilySearch to see if they have BT's for Meshaw, not all have been indexed so you might need to browse them.

I don't know what the source was for the record for her on Rootsweb, was one quoted or was she just recorded in someone's tree. Rootsweb is still not available so can't check.

If you can't find a baptism at Meshaw you will need to check adjacent parishes and also checked Non-Conformist records for the area. Remember that not all parish registers are available online.

I do have children in some families where I can't find a baptism for them, for some reason they seem to have been missed out especially if the couple had a lot of children. I also have some that were not baptised until they were adults so be flexible with dates when searching.