So was Oden weaker back then
Both were young and not in prime.
Pre timeskip Marineford Luffy was very strong for his age. He was above rear admirals and equal to some Vice Admirals.
He was halfway to mastering his Gears.
In Marineford, his Gear 3 did not have the shrinking drawback and his Gear 2 caused less strain on his body. He also used Observation Haki against Mihawk( Mihawk commenting on Luffy being calm) and Conquerors Haki in Marineford.
He one shotted a giant at Marineford.
Age 17 Luffy was very powerful. I never knew how strong he was until this chapter came out.