Accept

It's a tough choice to make, but you think you can do it.

You know your sister. She will either come back in time for the wedding, or come back and properly refuse to get married. It's not like her to just run away. Plus, it's only going to be temporary, right?

"Ok, I can do it." You say, though your voice is soft and weak. It's still a hard thing to accept. You do feel a bit excited at passing as your sister though. After all, she is quite popular everywhere she goes. Being the center of attention for once might be fun.

Your parents are obviously rejoiced at your choice, and proceed to plan the next steps.