Well let's see, Dark Elf necromancers make excellent first characters because of their ability to perform well without good gear or friends! They can solo very well, add tons of DPS in groups, are extremely versatile when fighting undead, can give their mana to other players (Like the group Cleric if he is low on mana and shit has hit the fan!), and they can feign death at higher levels to avoid a lot of bad situations.
Since Dark Elves start in Neriak you'll be very close to East Commonlands where it's very easy for a new player to get some help and learn the game in relative safety. EC Tunnel is where everybody congregates to sell their loot, buy new gear, lose all their money to gambling, and there's almost always someone willing to buff lowbies if they just ask nicely. You will also have no problem finding people to group with in that area because there's everything from snakes, bears, willowisps, to orc camps, and a really cool dungeon named Befallen one zone away in West Commonlands.
Int casters are also a good choice because there are many incredibly useful items like
Mystic Cloak that are easily quested and will help you save some plat early on when you need it for spells and/or billions of bone chips.
Hope that sheds some light for ya. If I were you I would go ahead and roll one up and try to work your way to level 8. You'll have a decent pet at level 8 and by that time you should have a good feel for how the DE necro ticks.
Like I said, they don't need much gear to be effective so you really only lose some time and will probably have made a few plat that you can pass to another character if you really aren't digging it.
Good luck!