Why would she text me that?

so i came on the bus after school (highschool) and my crush was sitting near the back and i sat about 5 or 6 seats down after about 2 min she sent me a text saying you couldve sat back here next to me...dont worry i dont have cooties :P and neither does sarah.........and i went and sat next to her after but why did she say and neither does sarah? does anyone have any ideas? thanks