do u see good deal then buy?

if you don't even know why you want to buy other than the good price, then don't even buy it, it's a waste anyways.

ask yourself what do you lack of from the 18-55 lens? focusing? IQ? build quality? or? If it's just little matter, then you don't need to upgrade at all. If it's more important things, like focusing speed and accuracy if you shoot moving subjects a lot, then consider to upgrade.

Even if it's a good deal, but if you don't really need it, it will only collect dust and left unused after bought.

don't need to any course for a beginner i think, there's plenty of useful information around the internet.

go to website like youtube/ 500px/ flickr more oftenly and you will slowly find the type of pictures you like then slowly observe and learn from the photographer.

don't buy better, use those money in places you need more.
depends, Av 90% of the time, M for flash. Tv for sports sometimes. Modes don't matter that much, as long as you know what you need to take control (iso? shutter speed? aperture?)