Hi Bairdie
Welcome to RootsChat

I assume this was David Baird b. 1778. It would probably help you if you worked back from the details you have for your David. Did he marry in Scotland, do you have the names of his children which can often provide clues?
Do you have your David on any census to try and reconfirm age (ie birth year). As ages on censuses can sometimes be inaccurate...so can ages on grave stones!
Be aware also that not all births were registered on the Old Parish Registers and if they were, a number of registers have not survived over the years.
The marriage/banns for the couple you have:
DAVID BEARD Marriages:Spouse: ISABLE COCKBURN
Marriage: 24 APR 1772 Foulden, Berwick, Scotland
Apart from son David, these children also show for them:
3. MARY BEARD BAIRD Birth: 27 MAR 1776/ Christening: 08 APR 1776 Dalgety, Fife, Scotland
5. THOMAS BAIRD Birth: 21 AUG 1780/ Christening: 29 AUG 1780 Dalgety, Fife, Scotland
These entries are all actual extract from the Old Parish Registers.
Regards.
Monica