I think even before thinking about online trading you really need to understand basic investing principles. That's a few steps removed from what you're looking at. I would at the very least pick up a financial newspaper to get a feel for that world or watch a financial news channel. Get the right foundations before exposing yourself to this eclectic world.
As with any sort of investing, I'd strongly recommend doing your research on specific companies before going in too hard. While it's true that the profit is there to be made, theres also a risk of taking a loss aswell.
Yeah, I started trading before there was online trading and it was a nightmare. I started investing when I was about 19 or so, and NOBODY would take me serious.. it probably didn´t help that I was usually trading odd-lots of less than $1000. It is funny, I still remember the smell of the office I had to go to ( Smith Barney). It was a little intimidating the first few times, but one of my earliest stocks was MSFT ( late 1980s), so I got a little confident just because that was hitting so hard. Nowadays.. no way.. who the heck wants to have to drive to an office to trade a few hundred shares every time you want to make a trade, and then wonder how many hours or even days after you tell your broker that the transaction gets made.
See, Forex is the best online trading platform cause still the majority of people are trading here even I think 20% of people are trading at FreshForex broker due to their honesty and accuracy.