I think the only one this might be possible with would be Skylar. IIRC, MC is 18, so born 2001. Most of the characters are the same age. The only ones who are older are Jessica, who Tiffany is already pregnant with, and Skylar. I don't think it is ever mentioned if she is younger than Jessica, though since Luna isn't pregnant (as far as we know) in 1999 she must be a bit younger than Jessica, so there is a chance MC is her dad from 1999 maybe.