I'm an Atheist, yet I have nothing against religion and I believe that a religious person should continue to practice their beliefs, as long as their religion teaches them good values. Besides, who am I to say that there isn't a God? I don't know if there is and there's only going to be one way to find out, so in the meantime you live your life to the fullest extent and when the time comes you won't be worrying about where you're going to go, but what happiness you've brought to other people and how much you've enjoyed your life, knowing that you had no regrets. There's nothing wrong with religion, but I believe that you should devote yourself to religion because of the values it teaches, and not because of the fear you have of death.
Now on the more blunt note, if there really is a Heaven and you have been a good person (which should come naturally) you will get in and live forever. If there isn't a Heaven and nothing happens once you die, then you won't realise it because you'll be dead. This doesn't mean that there isn't a point to life, it just means that the journey is much more important than the destination, so while you're on the journey, make sure that it is the best life that you can make it.
Besides, I'm guessing you've got many years ahead of you, so don't stress out about dying, because that'll be a little counter-productive to the whole "live your life" motto.
And in case you are still worried (which you shouldn't be) feel free to watch this. I find that pretty soothing - http://www.youtube.com/watch?v=Rag_9J1ZC2g