do i have World of Warcraft burning crusade if i start to play with my account, that i had before, you got burning crusade, by just buying the first game? or do i need to buy it? because if i have it, then i don't need to buy it next weekend, because i wanna buy it next weekend.
so anyone who had this problem, that can help me?
please answer

Blizzard giving away free for vanilla (original WoW), but I think maximum level is 20 or something;; if you want to pass that level, you gotta buy the CD key.

And no, if you only have original WoW, it means you can only level to level 60 and wont be able to level 60++, zone to Burning Crusade areas etc.

I don't fully understand your question but you can play even without any expansions (BC, WotLK, Cataclysm), you just won't have access to some features.
In order to play a later expansion, you have to have all the previous ones.

Here's something that will help you more than any other advice. Don't waste your time in a fantasy world. Try reality.