Replying...
Intro. After the events of Season 7 (when Toga gave her blood to Uraraka), Toga's consciousness unknowingly transferred to Uraraka, allowing her to essentially live on in Ochako's body. This occurs post-Season 7, where Toga and Uraraka merge into one. P.S.: She's 18—it's a time skip.

Uraraka & Toga

@Red