Help with mormons please?

So, I come from a slightly unusual background. My mom is a mormon and my dad is a United Methodist. I was baptized in the Mormon Church when I was 8 (I really just wanted to be dunked in the water. I didn't really care about religion then) and was recently confirmed in the United Methodist Church at the age of 13. Both churches have very different beliefs. I prefer the United Methodist, but I also love my mormon friends at the other church even though I don't go. Now, a lot of mormon kids at my school are pestering to get back in the church again and I keep trying to politely tell them that I'm happy with the church I'm in. But they won't take no for an answer! How do I nicely tell them that I just don't believe in Mormonism without losing some friends?