С нами и со мной

[gnomygnomy.livejournal.com]

Hello again! Today after class my friend asked me if I wanted to go to the movies with her tonight. When she asked, she used с нами and not со мной, but there wasn't anyone else going at that point. I tried to correct her and she said that's how they say it, even when it's only one person so far who's going. Is that right?

UPDATE: Thanks, everyone! She still thinks she's right, but now I know not to put much stock into what she says.