Lol stop the compliments please.
I dont think age really matters in this matchup. I think what matters is if Mereum knows the Gungi tactics or not. Once he overcomes the buddha, Netero is a sitting duck.
However if Mereum has no knowledge of Gungi, then potentially even Old Netero could defeat him. Within 40 seconds, Mereum felt dull pain from Netero's attacks. And if Netero can keep up the buddha for 16 hours....that means he would eventually kill Mereum within that timespan.
All Netero being younger would do is speed up the process by landing harder hits on Mereum.
Conclusion...if everything was the same but Netero was just younger. Than Mereum would win....