The fundamentalists tell you that you must be "born-again" in order to enter the kingdom of God. While their contentions on John 3:16 are actually the result of an appalling lack of theological knowlege and any understanding of period Jewish religious customs -- and while the Bible upon which their contention is based is not a godly document but an imperfect and human one (have the courage to explore the documents in our "Bible" section) they are right about one thing. You need to have new life if you have been involved with their religions.
Free yourself of false religion (fundamentalism), and seek a life, a new life, for yourself. Put into that life the things that you want there. Include friends and loved ones. Exclude people who bring you down or try to drag you back to fundamentalism. Stress your freedom, if they cannot deal, you do not need them. Include positive decisions, good food, good times, laughter and love. Include sex if you want it, and are ready for it (and legally old enough to engage in it in your community). Harm no one. Care for everyone.
LIVE! You deserve it, and you can accomplish a great deal. If you want spirituality or religion in your life, seek a faith that suits you and that will be supportive. The United Church of Christ, most Episcopal Churches (but not all -- ask them bluntly about what their views on inclusiveness are), many United Methodist and United Presbyterain churches (same caution), Reform Judaism, most Reconstructionist Jewish Synagogues, the Unitarians, Buddhism and some forms of Hinduism, some Sufi Moslem groups, most Wiccan groups (particularly the Correllian Nativist Tradition), Liberal Catholicism (a small denomination, not a statement about some American Catholics - although despite its homophobia and other negative stances, if you can ignore those, Roman Catholicism has its heart in the right place). There are lots of others. Get involved where you are comfortable and where you feel love being directed to and from you at the same time.
If you are not interested in religion at all -- that is also cool. Atheism, while it can be as shrill as fundamentalism is a perfectly viable option for many. Follow it if you are interested, or simply be non-spiritual. I happen to believe, but I also believe that god(dess) will never reject anyone just because they don't believe in him (her). That would be silly of a superior being, so don't sweat it, if you see no reason to believe, then don't.
Be ready to defend your choices. If you are so inclined read and study -- no fundamentalist is any match for a well learned and determined non-theist, theist, or mainstreamer. The facts simply are against them, so no matter how bright they are, as long as you are ready to argue and are knowledgable and unwilling to be manipulated or snookered, or so polite you back down, they will lose. If you are not inclined to defend yourself in a debate or are not ready to fight back, learn to simply say firmly "I have made my choices and have NO interest in hearing from you or debating the point." If they persist walk away.
Continue to free yourself of the preconceptions of fundamentalism. Get to know people that fundamentalism says you should not know. Make friends with those who are outcast or downtrodden or poor. You will be surprised at the uplift in your life that will occur as a result. Look into biology and if you want into alchemy. Expand your mind and enjoy it and your body, safely of course.
First and foremost watch out for the low points -- that is when fundamentalists will be lying in wait for you.
Lastly but most importantly, remember that you are great!