i played skyrim and oblivion and loved them and in always play as a dark elf so i would love to see Vvardenfell and i want to get it on pc as i heard it was really laggy on xbox 360 it is 20 euro on steam at the moment so isit worth it

You just missed the sale on Steam, it was 5,- Euros.

For me it is worth it, but if you can find a retail copy, it'll be even better. Just bear in mind that Morrowind is hugely different than Oblivion and Skyrim. http://www.uesp.net/wiki/Differences_Between_Morrowind,_Oblivion,_and_Skyrim should explain man differences.