Yeah, I was being a bit cranky (see, the lag issue has been around for about 2 weeks for some, and sometimes for many, & it has been commented on several times).
When your account is running again, look at the ping rates by hitting the 'connection' button on the shard selection screen. There are two locations of shards in the US: west coast and east coast. One location should be a bit faster for you. That will narrow down where you might like to start.
Then if you want a high or low population shard, hit the '% Full' button during your peak playing time over a few day period and that will help you decide where you might like to be.
As far as maturity and all that.. I think you can find what you're looking for on any shard; but it may take some time to find it.
Try looking at the forums for each shard here on stratics & that might help you hook up with some players &/or get a feel for some of the people on the shards.
As well, people do play multiple shards and several use character transfer tokens (I think about $15-20 per character & sometimes people sell them for gold in the game) to hop around on different shards.