i want to be a dark elf and my friend is a cat person i think they are called kajits or something like that and they are in different alliances so will i still be able to be in their game and do quests with them?
The easy answer to your question is no, you cannot play with friends in other factions. However, if one or both of you have the Imperial Edition of the game, then you can make a Dark Elf in the Dominion faction (which is the Khajiit faction). Or your friend can make a Khajiiti the Ebonheart faction (which is the Dark Elves' home faction). Basically the Imperial edition removes the restrictions that keep you from rolling any race in any faction. You just have to select the right options on the character creation screen. There's a bar for race, and one for faction.
That is only if they pre-ordered the game and got the explorer's pack which was available to Imperial and regular edition..However if you get the imperial editon you can be an imperial as any race. http://elderscrollsonline.com/en/joinus as it shows on the store site...you can also reach that site by going to the homepage.