Drabble #22
After the war ends Harry takes Teddy and moves to Forks to raise him in peace. There he meets Rosalie who develops a soft spot for Teddy (for being a cute baby) and Harry (for being a good dad). Rosalie offers to babysit Teddy, while Harry is at work. They get to know each other and fall in love.
Harry finds out she is a vampire after a background check on her on her family but finds nothing of concern on her.
(Harry likes to spend his money on her and Teddy)
Rosalie and Emmett mutually broke up with each other before moving to forks.
Harry Potter's timeline was moved up by a year (the first year starts at 12) so Harry is 18. (Harry was born in 1987)
Rosalie didn't want to deal with high school again so she stayed with the Denali Coven for the first 2 years that the Olympia Coven moved back to Forks.
Only after Edward comes to visit (after he meets Bella) does she go back to help deal with the situation.
Rosalie was canonically turned at 18 so when she moved in, the Cullens claim she wanted to finish high school where they had previously lived and had stayed with family friends, but she had graduated the last school year and wanted to move back with her family.