Albert Lammertsz Myburgh (Meijburg), b2 - 10 year age gap between 1st child and 2nd

Private User, where are you getting their marriage 5 years later from? According to the timelines I can see, they are together on the 1707 muster rolls (no formal marriage record), when she is about 14, Lambert born when she's 15, and the next one (Willem) 10 years later, when she's 25. I suspect that she got pregnant out of wedlock (he is much older than she is), but can't tell what happened after that.

That's part of the problem. I don't see a record of their marriage but it here on Geni and Wikitree and on many other trees. I can trace FamilySearch baptismal records for the children listed.
The other is that there is still a big gap between the 1st and 2nd child. I wonder if there are
a) Baptismal records missing
b) They had a child Lambert out-of-wedlock. He was then involved with someone else? Their 2nd child is born when she is 23 yet fertility doesn't appear to be an issue?
c) There are baptismal records missing?

I don't see an actual marriage record anywhere, but I think the marriage here is assumed as they appeared as a couple on the muster roll in 1707, 1712 and 1713. (Also assumed by Richard Ball on [http://www.ballfamilyrecords.co.uk/burger/I117.html his family records], but [http://www.e-family.co.za/ffy/g8/p8128.htm#c8128.2 First Fifty Years] uses c.1711, as they had appeared as witnesses to a baptism on 27/ 7/1711.

I really don't know- but it does seem to indicate that they were a couple in the intervening years, as far as I can see.

I see that Wikitree has assigned a marriage date of 17 October 1715: https://www.wikitree.com/wiki/Lammertz-1#Marriage - however, the source for that is not clear.

Thanks for sharing this info Melanie. The assumption on c1711 seems more realistic. I wonder if they lost children in small pox epidemic and the records have been lost.