First, it is impossible to overdose on Marijuana. Tests have shown that the ratio to overdose on marijuana is 40,000:1. Alcohol is 4:1. There have been no reported cases of dying from marijuana overdose.
Alcohol gets you drunk by producing toxins to kill brain receptors. Weed, stimulates brain receptors, but does not kill them. Studies show that there is 0% possibility of brain damage from smoking marijuana.
Marijuana has been proven to reduce, and in some cases eliminate, brain tumors.
Marijuana HAS been proven to cause lung, throat, and mouth cancer. However, the risk is substantially lower than smoking cigarettes. Also, inhaling anything that contains burnt carbon-matter can cause cancer (Like campfire smoke, burning paper, etc.), and the risk of cancer from smoking marijuana should only be a concern for chronic users, recreational users don't have a very high risk. Using a vaporizer (you can make one out of a lightbulb) practically eliminates this, as nothing is being burned and the THC (chemical that gets you high) is being converted from a fatty substance in the weed directly into a vapor, rather than smoke.
Marijuana is 0% addictive. There is no withdrawal from abstaining from weed.
Marijuana is not a gateway drug. Studies show that average people who smoke marijuana are not lead to harder drugs because of their past marijuana use. When the Netherlands legalized marijuana, cocaine and heroine use went down, rather than up.
If it's your first time, you more than likely wont feel anything. It wasn't until my third time that it hit me, and oh was it amazing.
Any more questions?