If your friends think little of you, they weren't your friends to begin with and you should find better ones who are worthwhile. They're out there.
Being an actress would be difficult. Look at the lifestyles many people in acting lead. If you can uphold your standards, more power to you, but it's not going to be easy. Just looking at a few of the people who were listed in other answers-- most of them aren't active members of the LDS church. They were active until...they went to Hollywood and got caught up in everything. Theater is different, of course, but Hollywood is easier to get examples from. See if you know any other LDS people in the same career path as you and see how they're doing. If they find they don't have too hard of a time upholding their standards and they don't regret their choice, then that's a good sign. You can still choose what you do and control your own life.
Also, it's not the church that does the forgiving; it's Heavenly Father and Jesus.