Convincing to pay for a decent gaming laptop?

Hello,
It's another one of those 'convincing parents for gaming rig' stuff.

Well, yeah, I need help convincing my parents to buy me this laptop.

I'm 14 and live in Belgium.
To be able to work you need to be 15 and in the year u become 16 (In my case 2016).

After I found out I can go earn lots of money in a year I got the idea of getting a gaming laptop: http/www.laptopshop.be/product/551928/category-180904/msi-ge70-2pe-632be-apache-pro-azerty.html

It's Dutch but u'll get it.


I've been looking around and found the laptop I want, I'm so excited but when I think of the fact it's still a year wait I get kinda depressed.
The laptop I have right now can't run any good game on a decent framerate, not even Garry's Mod.

I'm so excited for this laptop I want to ask my parents to buy it for me already.

I need some tips but I found somethings myself which might work.

1. I have €300 on my bank, and I'm ready to spend it all on the laptop.
2. I'll pay them back, even double when I have work.
3. The laptop I currently have will most likely break soon while a gaming laptop will last alot longer.

I'm kind of afraid to ask because I've gotten so much already but this laptop would be the last thing I'd ask for.
Will these arguments work? Thanks already!