1,2,2,3...sounds like you already are high. j/k. Yeah you can smoke by yourself, but it's easier to do with someone who has before. Or it was for me. Make sure there's no way you can get caught so you don't have a panic attack. Make sure you break the weed up. Don't smoke too much. def. don't smoke all of that by yourself. Unless you want to be really stoned, but there's no such thing as overdosing so don't worry about that. The effect depends on what kind it is. Check out erowid.org and click on cannibis. It will answer your questions on how much, and the effects. Have fun man.