For individuals that lived during a time of no vital records, genealogists often do not have dates of birth for their long-dead forebears. In some cases, it may be difficult to even estimate years of birth. Genealogists and software programs like to put children in order. In cases such as these, make certain that you indicate the birth order is either a guess or inferred from the order of children in a will or another document. If children married, years of birth could be estimated from the marriage dates (if available). If the ordering of children is done based on when they married, indicate that as well.
And ask yourself, would any of my conclusions change if the order of birth for these children change? Most times they wouldn’t, but you never know.