I have been diving into old Bitcointalk posts recently and when i find something cool, i just want to share with the world :)
So SlushPool is currently the oldest Bitcoin mining pool, mining their 1st block 97,834[https://mempool.space/block/000000000000dcaab612dcfd2a7b281c794a6da9006773dab55141ac608bfc86] on the 16/12/2010.
Slush made an announcement[https://bitcointalk.org/index.php?topic=1976.0] on the 27th of November 2010, but launched the server on 16th December 2010 [https://bitcointalk.org/index.php?topic=1976.msg30520#msg30520]
Currently, they own ~4.7 of the total hashrate.
So who was 1st?
On the 1st of December 2010 doubled made a post [https://bitcointalk.org/index.php?topic=2027.0] on Bitcoin talk announcing he started a "pooled mining server" using puddinpop's software(there was a LOT of drama with this guy and the 1st GPU miners, but that's a different tangent).
The 1st block their mined was 95,420 on 04/12/2010, well before Slush.
I guess the conclusion is that 1st almost never matters?