TOEFL Writing & speaking!!!

ok so I was practicing for my TOEFL exam next saturday and I wrote this essay in response to a lecture and passage about the system for classifying students according to chronologicl age in schools and how students have to repeat grades if they fail and how this system is very bad. Here it is: The professor casts many doubts on the system of school orginization which the United States has copied from Europe. Firstly, in the passage it states that at the age of six most students begin school. The professor says that this is wrong, on account of some six year olds are not mentally, physically, socially or psychologically ready to enter school while some are perfectly ready at the age of five or even four. This makes problems for the students in class because while some are perfectly ready to learn and study the others are not catching up with the material because they are not ready. Secondly, the profesor states that students in intermediate and secondary school are teenagers who develope differently. An obvious fact is that boys’ and girls’ maturity rates differ at these ages. Girls tend to mature physically and socially faster than boys. Just because some students are slower at learning that doesn’t mean that they have to repeat an entire year because of one subject they have not met the minimum requirements for. This is an issue of promotion. This system causes many dropouts because of the boredom that the stuents have for repeating an entire year of the same subject just for one subject that they weren’t doing well in. Lastly, some students in a class may learn slower than others. This causes them the need to repeat the class or maybe even the entire year while they only need to repeat the materials that they have not understood. On the other hand, some students are faster at learning which in turn causes them to have to wait for the new learning materials. This is not fair for both the sides because of the difference in learning rates. Thus, in conclusion, I would say that the professor haas the right for casting doubts on the system because it has many flaws and needs to be revised by the ministeries of education.

good grammar, vocab, and word usage? and if you have any speaking topics please tell me them!!! I suck at speaking for 45 seconds!!