Dawn – the writing is good so as a piece on it’s own it reads well.
However diary structure is very hard to make into a whole novel because you should only ever write what the character is aware of. And in a diary full dialoge is an alarm bell as who really ever remembers the full conversations they had that day?
You’ll find yourself struggling for a decent sized word count and making it meaty if this is the whole style of the story.
As an opening it doesn’t grab either, if it was written as prose you might find that the ideas you have here can be used as phasing and you could flesh this out nicely with one or two chapters of story.
The characters you have in here briefly would be great to develop and the little encounters themselves, the track training, the football match on TV, and so on.
In short try approaching your content here in a different manner. Go for prose straight up in a manageable tense. You could find what here is only a few hundred words become a couple of thousand easily.