since you want to go into history: who was there first, the albanians or the serbs?
I rest my case.
The Serbian medieval kingdom weakened in the 14th Century and finally fell to the Ottomans for good in 1459(?). Few Albanians lived in Kosovo at that time. In 1690, after a failed Austrian invasion which the Serbian population backed, the Serbs--fearing Ottoman reprisals--fled north in what is called the "Great Migration." Albanians from the surrounding area then migrated into the lands they left behind. Most historians date Albanian predominance in Kosovo from the mid-18th Century, although Serbs debate this.
Serb nationalists even say that Albanians did not become the majority in Kosovo until after WWII, in spite of census date from 1921 and 1939(?) showing ethnic Albanians at over 60%.
So, who was there first? Pick a date and pick a side.