I guess in my youth I was lucky.
I was surrounded by a lot of people of faith, even my football team and track team we would pray a lot before a game so I never felt like some Christian outcast.
Obviously I wasn't always surrounded by believers. Whenever I was the odd man out, I Just remembered that the best way to attract others is by example. If you are a positive person and a good friend, people will respond favorable to you.
One of the best ways I demonstrated my Christianity when I was young was in my willingness to help people. You help someone while being sincere, it is almost impossible for them to not respond favorably. Even if they disagree with you, you serve as an example to them that will draw them towards God. Whether it is helping with homework or helping them do a task, doesn't matter. Just by virtue of being willing to help, you bring those you are helping closer to you and God.
Lastly, in terms of handling rejection. That's okay. Instead of thinking of it as a purely yes or no thing, think of it as two separate locations: No to God and Yes to God.
On one side is NO on the other side is YES.
Every time you serve as a good example you bring those around you one step closer to god. Now, some people may require ten steps to get to god, some 20, some 100. But eventually, if those people get enough steps in the right direction, they will eventually get to "yes".
So don't think of it as rejection, but rather that the step you inspired didn't quite lead to yes yet. but because of you, they are one step closer and maybe the next Christian will get them to the finish line
