GCSE German help ASAP urgent

I've not gone through it in depth, but I don't think this is above a C. Apart from the fact that there are a lot of grammatical errors, it's very grainy and doesn't flow. It feels like a jumble of short sentences rather than the narrative it should be.

You should add some nice sentence openers like:
Auf der einen Seite...
Einerseits...
Also try to talk about different things instead of just tennis. I don't know what your topic area is, but your essay surely is too much about the same thing.
Also, the last two sentences are contradicting each other.
Try to stick to the right tense. In the first paragraph you're saying that you will go swimming next summer and then you say it is great, but you haven't done it yet, so you have to say "Hoffentlich wird es spitze sein" or something similar.
It doesn't really flow; it's like you are jumping from one thing to another without explaining it in detail.
I'm sorry if my criticisms sound harsh; I'm just trying to help. I'm an A Level German student, so if you ever need any help feel free to pm me.