Even if you are only 20 it should be fine. As long as Shadow and I are a high enough level, we should be able to last long enough for you and Aimless to take them down.
Shadow and I can make Death Knights on any server (Shdaow actually has one on Terokkar) so, getting you leveled up should be quick. I recommend going a DPS class of your choosing. Right now Shadow is a tank and i'm a healer.
Since we have 2 Hunters in the group, how about a Rogue?