Death certs are often the least accurate document when it comes to age/year of birth... it's possible the informant didn't know, or overestimated
Pity the marriage is before the start of civil records, since a cert would give you father's name, which would help confirm, or rule out, the connections. I presume you've already searched the RootsIreland/Rothe House records for possible marriages in church records ?
That death cert might be worth a try anyway, as it would give place of death etc, and the informant might be a family member which may allow you to check if it's the correct person.
Shane