Does anyone know...

"War;827038" wrote:
It's when you first created your account, every I want to say month, a new server is created. Which is why people will mention they're on a December shard, August Shard, etc.

There must be a bit more to it than that, since at the beginning of the month it would be a near empty server. Which I don't think happens. But that's the general idea of it.

A new shard is created when the current shards hits 20,000 members. You are assigned onto your shard as soon as you hit level 8 (when you unlock arena). I'd say a new shard is created every few days.
So, to answer the OP's question, you were put on a shard with people who started at almost exactly the same time as you, so there's no reason if you've been farming the right characters, you can't get rank 1. Also, power is only a number. It is no real representation of how good the squad will be you're about to face. It is more about the characters, their gear levels, and how good their mods are.