Early Arcane Mage PvE

So I rolled an orc mage last week. I've been flying through the levels.. But nearly every dungeon I go in, I am usually middle of the pack on Dps... But total damage I am always dead last. My rotation is...
Arcane blast x 4or5
Arcane Missles
Sometimes Explosion
Repeat.
Am I doing it wrong?
Are other classes just that much better?
I'm relatively new at mage.
My main is a hunter which always tops Dps and damage done. So I don't think I'm just a bad player.
Help please! :D

Bump
Im not the best mage in the bunch, after all this is more of my "fun" character than an actual main and I just recently hit 80 with him... To put some more context on it, youll notice I got my engineering motorcycle well before I ever hit 80 and that Ive probably spent more time working on Insane In The Membrane than I have actually raiding anything.

That having been said, I can pull off some pretty decent numbers in raids as arcane. Infact, I can usually beat = geared people, and hang with those just a little better geared than me, and only trail those who are deservedly better geared than I am. Soooo since no one else is replying-- Ill give this a stab.

Youre low lvl. From now till 80+ the class balance will shift greatly with passing lvls. Sometimes, because of talent unlocks, you may find yourself leading or being led by the pack on the DPS charts. This is fairly normal. Now is not the time to fret.

Stick with your current rotation. Stack up blast to around 4 then pop your missles if its up. If not go ahead and lay down another blast or two before dumping it into a barrage if need be to reserve your mana. If mana isnt an issue blast away till Missles proc.

AOE really only comes into play on very large #s of mobs. Rarely is it worth it.

Keep molten armor up over mage armor. This will buff up your burst dps, switch to mage armor when you need the mana. You will want to learn to time your fights. If a fight is short you can hold off switching to your mage armor for regen longer. On longer fights or fights where you cant stop to mana up you may want to go ahead and mage armor half way through the fight to keep your mana going.
I have the same issue with my lvl 32 mage. I was arcane at first, swapped to fire, I get a little more dps, but not enough to matter. I have no heirlooms or anything. I think it just has to do with class mechanics.
You also only have one heirloom. Most people you see in dungeons these days are going to have a full set of fully enchanted heirlooms. Don't expect to compete with them.
Have you ever considered that the other players might just be better than you?

Or perhaps they're just not as balanced at low level as we'd all like to believe.

You shouldn't care what your DPS is at level thirty-whatever unless things not dying fast enough is whats causing wipes.

You shouldn't care what your DPS is at level 80 unless things not dying fast enough is whats causing wipes.

You shouldn't care what your DPS is at level 85 unless things not dying fast enough is whats causing wipes.

The WoW player base has gotten WAY too focused on "I need to get my numbers up to be better?" and not "How can I play differently to ensure my groups success?"
It's been said, but low level DPS really doesn't matter all THAT much, though I myself haven't hopped on any of my alts since they scaled up lower level hps a bit. Your spec could be misconstrued for your level, which isn't a big deal, other classes might've just gotten a big spell that boosts them up a bit, they could have better gear than you - e.g. lucky green drops, lucky dungeon blues/bag blues, ideal heirlooms, enchanted gear, etc.

Oh, and if your mana can take it you just spam Arcane Blast. Missiles/Barrage only when you can't sustain a Blast Spam rotation for at least a full pull. Blast is and will remain your highest damage/cast/time ability.