When I write, I often use very long sentences, such as 50-word-long sentences like these, instead of multiple short sentences because I forget to end my sentence as I have so much to say so I don't think about keeping my sentences short to make the sentence's reader understand it more easily, and I also add many words that I do not need to them, which makes them even longer, but they're still grammatically correct, so there's no problems and I shouldn't lose points whenever I use them in an essay or some other text which I give to the English teacher, or another teacher such as the french teacher or even the math teacher, and they should be understood easily by anyone, including people whose first language is not English, so I was wondering if this is a bad thing or not, because if it is, in which case I would like an explanation why, I would like to stop using sentences like these because others won't understand them. 

So, should I stop?