nice to hear from you again.
Denny is right, in general there are no age requirements you need to fulfil in order to marry apart from being 18+ years old. But you have to keep in mind that Ausländerbehörde might get suspicious if your partner is way older than you. It could happen that they start investigating whether it is a fictitious marriage (--> a marriage that is only contracted to obtain a residence permit for a foreigner by fraud) or if you are actually living together like a married couple.
To get information about the marriage procedure in Germany, please check out the article about this topic published on the Wefugees blog. You can find it following this link (scroll down a bit for the English version):
Regarding marriage in Denmark, keep in mind my answer in your other thread:
I hope this answer was helpful to you.