The Wikepedia time line is totally internally consistent:
Born Nov. '42, Graduate HS spring '60 (age 17, almost 18), start college fall '60, meet BHO, Sr. fall '60, pregnant, Nov '60, marriage Feb '61 (Parents object, but hey she's 18, so what can you do?), Jr. born august '61.
The alternative is impossible to make sense of: Born in '42, marries BHO, Sr. at age 16(?) (where, in Hawaii? what's she doing there? when did they meet?) , then back to Seattle to finish HS, then back to (??) Hawaii, then pregnant in nov 60 and junior in aug 61.
Wikipedia is supported by Stanley Ann and her attorney who stated in SA’s divorce pleadings v Sr. that they were married on 2-2-61. That may be the best evidence.
The official gov document may include an ordinary mistake. If the date was submitted intentionally, however, the question is what factual pattern might be established with a 1959 marriage?
Does it fit an older age? Or, was it just another example of a spiteful, immature response?
Seems like it hasn’t been looked at very closely. Probably isn’t that important to some people.