I am a fraternal twin but me and my sister are 3 and a half years apart?

So i have new about me and my sisters being fraternal twins for a while. No one ever believes me when i say i am. So this is it.. My Mom needed help... she got pregnant with in vitro fertilization and me and my sister were frozen and conceived at the same time. But i was born 3 and a half years before her. So technically I am? Right? Is anyone else out there with the same story? Thanks!