Most people don't get high the first time because they're physically unprepared.. The THC receptors in their brains haven't been woken yet.
I got a little high my first time, not nearly as much as I have been getting since I've become more seasoned.
The first time all I felt was a little float-y, as in my arms and legs seemed to drift away from my body when I held them out to the keyboard to type.
I was also playing assassin's creed and at one point I was just staring at the screen as ezio was continuously running into a wall.
But really thats just the way I feel when I'm tired sometimes, I'm losing the feeling in my arms right now and I'm completely sober.