How Do I Change?

I go to church, and do things for God willingly. I have only been saved for three years and I now have a fire for God that makes me feel alive; the more I stick with it, the stronger I feel. I'm starting to read my bible, about to join choir, praying, and getting active in my home church... but isn't it so easy to change around people that go to the same church, that have the same beliefs? I feel so strong but I also feel so weak. How do I change in my world, my environment I live in? For I have lived a lifestyle as a sinner, even while I was saved. I want a difference NOW, but I don't know how my friends and co-workers will take me. I haven't been a good person, spiritually and worldly, and now I want more. When this question first came upon me, I talked to the pastor and he told me not to be scared. For if they notice a difference in me and notice my walk with God, then in that small deed of following in God's footsteps that I am professing his name before man. If your to scared to change in your worldly environment, then are you truly saved? If you do change, than it profess' Jesus as your God, and proves your salvation in God. Knowing that you are saved and will go to heaven. And if that is so?... why wouldn't you want to change and profess God as the only way.

"Therefore, prepare your minds for accusation; be self-controlled; set your hope fully on the grace to be given you when Jesus Christ is revealed. As obedient children, do not conform to the evil desires you had when you lived in ignorance. But just as he who called you is holy, so be holy in all you do; for it is written: 'Be holy, because I am holy.'" 1 Peter 1:13-16 NIV