Assume that the future can change based on your actions, so any historical information that you bring along with you from the intervening 25 years may quickly drift out of the new realities history.
Edit: also assume that you can be given a healthy 21-year-old body if you want or take your previous self’s place.
Further, identification will be provided for you if you were not born at that time.
There is a subplot in the INVINCIBLE comics that follows this very premise, and chooses the same decision you do for the exact same reason