ok, well here are my thoughts:

First of all, you know that you could potentially throw away a major part of your life if caught. Not saying that you will get caught but it is illegal and if dealing chances are it won't be misdemeanor possesion, it'll be felony possession with intent to distribute. So you must accept that as a possibility.

If you can, then next you need to realize that it is more difficult to make a big profit off of weed in the same quantities as you can other, harder substances. This however, can vary geographically. If there are other rivals in your area who are well established with good sources then they can afford to sell higher quality at lower prices.

You will be starting a business (albeit an illegal one) that requires some work, but to me in dealing the biggest way to establish yourself is to be honest and fair with your clients. Give them a reason to keep coming back and they will, remember this is an entirely word-of-mouth enterprise.

That being said, living with your parents (which I must assume you do based on context clues) makes this even more difficult because your availability is lower than someone who is perhaps a bit older and has their own place. Remember, when people want weed and know several individuals to get it from they will generally buy from the person that:

1. Can get it fastest (nobody likes waiting, especially to get high)
2. Can get it cheapest (this is just simple economics)
3. Can get it consistantly (not just every so often)
4. Can be considered a fair and trustworthy dealer (human nature)

If you ask yourself if you can satisfy these criteria then you should have no problem, but most dealers really sell so they can smoke for free and have a little cash on the side. To turn a profit big enough to count as an income, then you would really have to move into the larger market of mass-growing which is a whole other ballgame.

Just some thoughts, good luck with your decision!