Maybe not a bad idea, I know many "normal" mechanics from MMOs are different in GW2, and I have read about alot of them.
Just need to pick my race also and such though before I know what I want.
I'll say this: after reading all of that same stuff and watching press videos before the public betas, and hearing about how different it was--it still didn't prepare me for what was truly different.
It honestly takes several hours, and at least about 8 or 9 levels to figure out
how not to die.
On top of that, you aren't quite used to the way weapon sets are tied to the skill sets, so many ignore weapon collecting early on. That's probably the most important thing--grabbing all the weapons your class can use, as soon as you can (drops or purchasing; though money is pretty tight when starting out in this game).
but there is also the early access prior to general release. Either use that as the learning curve, or use it as an advantage for leveling.
as for your classes--I played my Mes up to level 29 through the previous events, and I thoroughly enjoy that class. now that she is wiped :\, I might go back to thief (played it briefly in first event, but felt that mele was punished in the first beta weekend build of the game--many felt this, but I also think mele gets much better as you level--or engineer. Many have been down on engineer, it seems. Not sure why--underpowered, not fun?
Nec is quite powerful I must say, and Ele seems to be really fun, though especially squishy.
Mes looks to be the best overall support class in PvE and PvP (especially PvP); but maybe I am biased.