Well I think you're a little young to start. I would wait a few years but if you really must, atleast make sure your priorities in check. All homework is done, you don't have any work, and shits ok at home. Don't start unless you know you can handle it. Weed is more or less harmless, I won't lie to you. It's wrong to lie to kids about weed, but if you do always remember to put real life priorities before hand. As long as you do, weed is a safe way to pass time. But always make sure you do.
So what to expect. It's common not to get high your first time. Don't know why, but it took me the second time to get high and what a rush it is. You will space out reallllll easy, so it's always recommended to not drive for a little bit. Atleast till you can handle weed like a pro. You will get very euphoric and probably feel funny. And it's pretty much extremely unlikely to see open eye hallucinations. You have to smoke ultra dank powerful weed and quite a bit to get to that zone of high. Also make sure you got plenty to drink around. Cotton mouths a bitch sometimes. The rest is all up to your body chemistry. Everyone feels high a little bit different then others, but always remember YOU CANNOT DIE OR GET HURT BY INGESTING weed. Ive seen idiots get real high and geek out. Just relax, you're 100% fine. Most of all, have a good time.
But just remember, don't become a fien. Don't be a little douche that doesn't do his work and only smoke weed. You can function plenty fine with some discipline and brains.
Good luck and safe toking