Investing is not a precise thing and nobody can predict all the variables, so there is always risk. A good investor has a percentage edge, meaning he will get more choices right than wrong. And, it's not so much just picking the right stock. It's also knowing when to get in and when to get out. If you look at the track record of any stock, you can see where if you bought at point A and sold at point B you would have done well. Having the ability to recognize those points is perhaps the single most important skill. Timing often makes the difference in winning or losing.
As far as an option to create wealth, investing is one open to everybody, and the little guy can get in anytime. There is no where else that has the potential investing can offer. It's possible to acquire most of the knowledge in the internet, and one can start with as little as $500, but more is always better.
One other thing- not everybody is mentally wired to be a good investor. The stock market behaves like a temperamental child, and many of the moves are erratic and illogical. This can be a good thing as it presents many great opportunities. The best investors know how to profit from that while those who lack the emotional control get sucked into the game and wind up losing. That capacity is hard to learn. For the most part, you either have it or you don't. I seem to have it; I have a 7-figure portfolio that started with 10K, about 16 years ago.
Made Warren Buffett what he is today.
bad idea,,, since you need to be 18 or older to open an account
It depends how much and where you invest it but I would prefer to keep it in an ISA account