When lot's of change happen's, it's not as exciting to an introvert as it is to an extrovert. Getting married sounds like fun unless your terrified of getting up in front of three hundred people and being the center of attention for four hours. Absolutely the most terrifying thing ever, yes, but also one of the best day's ever. As an introvert I don't remember all the people I had to talk to, I just remember my husband who took the lead on talking to everyone.
Moving to a new town is scary, especially for an introvert who was kind of sort of comfortable with her old friends. Now having to make new friends is a new challenge. They won't know anything about you. They won't know how socially awkward you are and might just think you are weird, you will actually have to talk, and worst of all you'll have to talk about yourself.
The plus side about getting married and moving to a new town is being alone. Not the bad alone, but the good alone. Where there's time to sit a home, start a new hobby, read books, and just relax in silence without anyone calling you to go to a party or have lunch and discuss life. The quiet life is nice.