You can use them all, they are all correct

It is entierly up to you which you want to use, there is no which one is better, they are all ok to use

Keeeeep on going no matter what, instead of getting depressed and spending a lot of time moaning and groaning and thinking about it- learn a new word - learn a new grammar point,  any new word you learn is a step forward, GOT IT ? Keep moving forward, sometimes i dont see any progress but i keep going, then 3/ 4 months later i ask myself: was i able to do this 4 months ago ? No i was not, therefore i have progressed without realizing that i learned a lot, keep going!!!!!! 

Schools are very expensive, get yourself a good grammar book, get a Italki tutor once a week, get a couple of exchange partners,( conversationexchange.com )(free ) within a year your English will improve A LOT

Hallo! Ich bin...

Hallo alle miteinander, ! Mein Name ist Dawson White, ich lebe in Kanada. Ich bin achtzehn jahre alt, und ich Lerne Deutsch seit zwei Jahren. Letztes Jahr reiste ich nach Deutschland, es hat mir sehr gefallen- es ist ein schönes Land. Dass ist alles für Heute, auf wiedersehen!

Korean from zero , written by George trombley, the best !!!!! You can get it on Amazon or any language book stores, each chapters builds on the one before, super easy to , check out his videos on youtube

Go on conversationexchange.com, create free account with email and password, there are lots of people there from all over the world who can converse with you for free, super cool website