A lot of people on this forum strongly advocate dirt, and it's a good substrate system. I'm one of those people that generally advises more caution with beginning tanks. I think about it as such:
What was your first car? Was it a nice car, or was it a beater? Like probably many people, my first car was a genuine POS, but it was 'functional'. After all, I didn't need an expensive commuter car or a muscle truck. Nope, it was a station wagon for me. It was however, a good forgiving beginner car. Let's face it, teenagers are bad drivers and giving one a muscle car is a recipe for disaster.
How does this translate to planted tanks? Sand, gravel, or other non-nutrient substrates (including fluorite and EC) are good starter substrates, whereas nutrient containing substrates (Aquasoil, dirt) are the 'muscle cars'. Having a nutrient rich substrate means that there will be nutrients available in your water column for anything that wants them, plants, algae, or otherwise. If you don't know how to manage the needs of your plants, you might find yourself with algae problems, or other common complications. I knew people who got brand new cars on their 16th birthday, and while many of them did fine, some people always wrecked their $10,000 life lessons.
Long story short: Do it if you want, but do your research before hand and know how to manage the tank. Dirt is really only bad in the hands of the uninformed and uneducated, imo.