Wait...so if you're an INTP you're automatically prone to liking weed? =\ why?
I don't necessarily agree. I dislike cannabis after having smoked a fair amount of it. I wouldn't advise against using it, but I would wait till 18+. About one and a half year ago my friends and I started smoking, now I'm a psychonaut with fair amounts of drug experience and they're, well, recreational users (for the fun of it) of both cannabis and other drugs.
Drugs in general show you aspects and sides of yourself difficult to find in a sober state, and this can help you develop as a person, -especially- psychedelics. You can also be confronted with several uncomfortable things about yourself. Cannabis is (and some will disagree) mildly psychedelic, and can shoot you into a mild variant of what one can experience on drugs like LSD, mushrooms, etc. Be prepared, it can fuck you in the ass. And by then you best know how to unfuck yourself.
I only smoke cannabis rarely now, after paranoia, anxiety and shitty self esteem creeps up on you, it's not much fun anymore. And it takes time to rebuild, but you become stronger and more self aware on the way back. Also it stops working in the fun psychedelic way after you've smoked for a while, building up a sort of resistance that simply won't go away completely.
Also, keep this thought/experience from me in mind (especially those who say cannabis is "not a drug"):
I've been on quite a few (different) trips by now (LSD, mushrooms, 2C-B, ketamine), and I've been down on the fun/fucked up drug department just to try it out (cocaine, GHB, benzodiazepines... alcohol). I've had mild benzo withdrawal as well (certainly not fun). But nothing, nothing has ever beat my smoking experiences from the early days. My most extreme and fucked up delusional/psychedelic expeirences have been from cannabis. And nothing has given me more shit to cope with than cannabis, except maybe that benzo withdrawal, but it was a lot easier to distance from than the cannabis related problems.
Beginning to smoke at age 15 might turn out ... bad. Beginning to smoke at any time, might turn out bad. But you might just have a good time, and be one of those lucky people that don't get problems by playing too much with weed. But most likely you will change, and, depending on many many factors, you'll also quite likely (from my experience, and what I've seen) try other drugs, as long as you're not one of those ignorant stoners that think marijuana is the gift to humanity and can't harm anyone, while LSD is poison for the soul.
I recommend waiting until you're 18 with any drugs, 20+ for hard drugs and psychedelics. At 15 you're still a kid. Playing with the mind is not something for kids in development. It can give you a lot, and it can (and will) take a lot from you, as well. In the end I regret nothing and would never ever live a life without visiting the extremes of our mind.
Use your brains in this game.
http://erowid.org/ has a lot of information for the curious.