Everyone makes mistakes when it comes to writing in English. I am in charge of writing articles for a news source, that will remain nameless here, almost once a day from October to June. I get some time off during the summer but I do enjoy my work.
I can tell you though that even professionals will managle a sentence or two every once in a while. It's really not that difficult to do. I also know when I post on a forum like this I do not really bother to check sentence structure because I couldn't care less if it sounds "professional". I save the "professional touch" for the articles I write. 
