If you draw well, it's actually not difficult to find people who will pay you to do it. In order to draw them as well as you'd need to, you need to spend every scrap of free time doing it.
I draw dragons, knights, spaceships and robots and I've had companies pay me pretty well to do work for them. I'm very young and have only just started, but am in the process of securing a full time job in London to do this on a salaried, rather than freelance basis.
In other words, screw her as far as this is concerned. She's wrong wrong wrong. If you love it enough to make doing art your whole life (and you'll need to), all you'll need is time before you've got the skills to make it your career.
If you want some excellent resources concerning how to go about this, go to www.conceptart.org/forums
. I can't express how utterly amazing and incredible these forums are for commercial artists. They can be brutally honest at times, but they know what it takes to be a real working artist and they'll help you if you've got the will to do it. If it weren't for conceptart.org I have no idea where I'd be right now, but you can bet it wouldn't be anywhere even remotely approaching as good as it is now.
And seriously, I've told people about it before and they've just brushed it off, but if you want to do art for a living *go*to*that*site* make an account and put all you have into making a name for yourself there and learn all you can. My username there is Tully.. feel free to PM me for help of any kind.
Good, smart artists don't starve. Work at becoming as good an artist as you possibly can and the rest will tend to follow (not automatically, but getting good is the hard part). Conceptart.org will tell you how.
On another note, could we see a drawing or two of yours? And how old are you? It doesn't *really* matter, but I'm just curious.