On the other side, if German is a difficult-to-learn language is a very individual question. Everyone has its own answer. Someone will find it easier to learn, while other are going to swear that its impossible to learn.
Of course the answer depends also on the person who is answering and what is his mother-tongue. If he is Dutch or Danish he probably already understand much of what he read and is only a matter of time to come along with German. Probably faster than an Italian, a Chinese or an Indian.
Another important factor is the age. Children learn languages faster than an adult.
Some think also the gender is making the difference, meaning that a woman who in average speaks more than a man, will have it easier to learn German. I’m not 100% convinced that there is a gender factor, but I don’t have a scientific statistic to settle the question.
I can say that also Germans sometime have a problem. For example for old people who have learned the language before the 1996, the orthography reforms (Rechtschreibreform) have brought some confusion in their ability to write German without any “error”, at least assuming as an error what is not conform to the new standard.
The younger generations for sure have been able to catch up with the reforms, in particular with the fact that everything is written as it is spoken. This is a big advantage for you as learner as well.
Another reason, why also German do errors is, together with maybe not perfect education, that many people write on PC, using automatic correction, so that the level of attention is low because anyway the intelligence of the PC will correct one’s error.
Then when we are in the situation to write a letter by hand we are in a situation of high uncertainty.
In addition, after you’ve finished you’re German course you are not going to refresh your grammar knowledge, and the rules will probably fall into oblivion soon. You rather speak and write how you feel is better, how it sounds better to you.
Enough reason to take a German course, to get more info go to my page German courses in Munich.