A 22 year age difference (woman in 30s and man in 50s) is significant, but certainly far from extreme. I would certainly never discourage it.
Furthermore, I know that you are a wonderful person
@Joleneakamama. I also believe your husband and sister wife to be people of excellence. I'm certain that your home and family will be blessed and happy. I rejoice with you all.
I would however urge serious caution to a 70 year old considering a 20 year old, and to a 20 year old considering a 70 year old.
I'd also urge caution between a Reformed Baptist and a Presbyterian marriage. They need to decide what to do about infant Baptism before the kids arrive.