Uhh well I can only go about this bluntly. You CAN'T make people watch anime. You can tell them about it and if they're interested they'll carry through but if not then you need to just leave it alone. Going by your post I'm assuming you're still in high school still. Although don't feel too bad I was like that when I was in high school as well so I speak of this from experience. Can't please everyone you know?
My family is also very religious so I don't discuss anime with them ever. When I was younger they tried to steer me from anime as well because its even more offensive in the christian community then anything but after a point they realized how much worse situations I could have myself in and left me alone to my devices (: Its just a matter of time, assuming you stick around(in the anime community) long enough.