In World of Warcraft can I go to lv 80 without much training

It takes quite a long time to get to level 80. Generally, around 48 hours of play-time, if you really know what you are doing. It takes considerably longer if you are new to the game.

Once you've leveled a character to 55, you can begin a Death Knight, which starts at level 55 and takes significantly less time to level to 80. Unfortunately, if you're new, this doesn't really save you any time.