Is it normal to be nervous 1 month before your wedding?

I have been with my fianc� for over a year. We have been engaged since before Christmas. I was nothing but excited & happy all throughout our engagement. Lately as the wedding is creeping up & less than a month away I've become nervous. I am committing to one of the biggest decisions of my life. I'm scared of our relationship changing after marriage. Is it normal to have pre-wedding jitters when the wedding date gets close? Does this happen to a lot of people?