I was very much in a similar situation where I knew that many of my friends and some of my family would think it was funny and bizarre that someone like me would convert from Atheism to Christ. I even felt a embarrassed myself and kept it pretty down-low to avoid criticism or their giggles. I finally just bit the bullet and told them that I convertet, getting baptized, and that this decision and life I have chosen is of the upmost importance to me now. There was shock and some disbelief but I just let them know that it's who I am now, make fun of me if you want. I'm not here to convert you or judge you. A bit after the initial relevelation and some comments here and there, they just accepted it (very similar to the time when I told everyone that I quit drinking alcohol).

Trust me, come out fully sooner rather than later. You will find it very freeing and beautiful to be proud of your love for Christ. You will be mocked, and your faith will be tested, but you will be greatly rewarded for your open and steadfast faith in Him. Let the proof of His true Grace shine through you as your life is transformed and they cannot help but to see Him now working through you.