Lovely to have a polite and respectful young man wander in here.
I agree with the advice offered above.
I also think you could switch up sentence structure so not so many beginning with "I".
I'm Simon, 22, I'm honest, confident and I love a good laugh. I'm very mature for my age, I pride myself as a good listener and being respectful to people. I can be a little bit shy at first, around new people, but that soon fades! We know your name and age. The rest is pretty much a bunch of cliches that everybody thinks of themselves, so try to describe yourself without using those words.
Do you tell jokes or are you funny?
When she wears an outfit she looks bad in, are you honestly going to tell her?
You're only 22 so I'm wondering what you consider being mature for your age.
So you're writing a book? Nice. Why so cryptic on the subject?
You also talk about it in different places-- keep it all together.
Break that big paragraph down so it's easier to read.
Go into a little detail about the interests you mention here.
She will feel free to send a message without prodding.
Your written word is a bit factual with no personality...try writing as you speak so it sounds less formal.