Is there a ledger where I can find mined bitcoins?
no.
The Bitcoin blockchain is a transaction journal but does not link mining rewards to people’s names.
I participated in the Bitcoin mining program in March 2008.
I remember that the Bitcoin “white paper” was written in late 2008 and published in early 2009. Therefore, in March 2008 it was impossible to mine Bitcoin. Bitcoin never existed. The first block mined, the Genesis block, was mined on January 3, 2009.