I'm sorry, but I do not agree that "I come from Germany" means you "did it".
I come from Germany = I am German
Examples of English usage:
"I come from Germany originally, but I am now living in France."
A - "I'm from Spain. Where are you from?" B - "I'm from Germany" OR "I come from Germany."
"I am coming from Germany" is a very unnatural and unusual sentence that a native English speaker would only use in a specific set of circumstances., e.g. "I am coming from Germany to your conference next week. Please tell me the best train station to use." , or "I'm sorry, but I'll be a little late for the party, as I am coming (back) from Germany".
If you wanted to say that you were in Germany, but are not there any more, you would say: "I came (over) from Germany last week. or "I have (just) come (over) from Germany.", depending on the context.
I hope that helps.
That sounds correct to me! Choosing which 'preposition' (little word) to use in German can be frustrating. But here you definitely need aus to mean "from" or "out of". When travelling to countries, use nach. Auf doesn't make sense in this context, kind of like saying "I come on Germany".