He was 15 when Roger died.
Find another cope lol.
Shanks was 13 when roger became pk
No way he can guess roger lvl at that time and age
He is still kid
...
Also even if shanks was like 20 when roger died
His words about imu doesn't tell that no exist can defeat him .
Its just tell how powerful imu is and how shanks is lacking in terms of power to the point he doesn't how powerful he is.
Also even if shanks who went to marigoa was 39 years this doesn't change anything
Cuz its normal for new hidden character to ambiguous.
Unlike other renowned like meme and Kaidou shanks can guess their lvl without even meeting them.
But someone who was hidden+ he is too powerful .
Shanks statement there is logical.