Some of you suggest calling the police? C'mon get a life! you make it sound like the JW are some sort of mind controlling oriental sect, which they are not. Although some "apostatas" claim so (I wonder what particular experiences they had).
Overall they are nice people. With a strong conviction but nevertheless nice.
Butterfliez, go to the meeting, always be respectful, for they will treat you with respect too, no matter which way you choose to go.
The elders are not there to brainwash you nor to push you into anything you don't want to. At least all the elders I ever meet where people with their feets safely on the ground. They will cite from the Bible, a lot.
One of the thing they may wish to gauge is if you fear men (your grandmother, them [the elders]) or if you fear God. If you are honest with them, explaining that you think you have been "pushed too early" into this or maybe only because of familiy pressure or whatever your particular situation is, and you explain that you need some time off. I guess they would have to respect that.
If for example it turns out that your family has been pressure cooking you into being a JW then the elders would have the duty to confront your family, not you, so as to have your familiy drop or reduce the pressure. The society does not want to "force" anybody, quite to the contrary.
It is also important to be clear if you belive that they have the truth or not. You may believe the truth is there but dislike preaching, the meetings, etc. be clear about what exactly you dislike.
If you just want "out" then respectfully say so. If you want a "time-out" to reconsider and think about matters, then respectfully say so.
All that said, i guess it can be psycologically heavy to suddenly loose all your friends in the sense that nobody will even talk to you (You call that disfellowship in english?). That is why i would suggest to go a non-confrontational way and just quietly wither away afterwards if you want to. That also leaves you the option to continue being a JW if after a time you think that is the way for you.
At the end of the road this situation is pretty unique for each individual is different.