I agree that there are better things for you to start with besides a kit. If you read through this article you'll see a lot of your options for making your moped faster. They're more or less in order of easier/less expensive to harder/more expensive, but obviously the order you do stuff is up to personal preference.
When you kit your moped, you're going to want to have a performance pipe on it anyway. Since the pipe is easy to add, that's a good place to start. You could also do the high flow air filter to help get the most out of your pipe, and DON'T FORGET TO UPJET. Adding the pipe first will help you learn how to tune your bike, which is a skill you'll need to have down before you add a kit.
Then, if you've got the cash, you could upgrade your carb to a 14 or 15mm Bing or Dellorto. This would also be good practice fixing and tuning stuff, and you'd probably get a little more speed out of it. Depending on your gearing, you should be pretty close to 40 by the time you add the pipe, bigger carb, and air filter. (Although there are people who do 40 on less, or who aren't anywhere near 40 with that stuff).
After all that, then I'd say you should kit it if you still want to go faster.