It is dogma that:
Our first parents, before the Fall, were endowed with sanctifying grace. (De fide.)
Also the donum rectitudinis or integritatis in the narrower sense, i.e., the freedom from irregular desire. (Sent. fidei proxima.)
Also the donum immortalitatis, i.e.,bodily immortality. (De fide.)
Also the donum impassibilitatis, i.e., the freedom from suffering. (Sent. communis.)
Also the donum scientiae, i.e., a knowledge of natural and supernatural truths infused by God. (Sent. communis.)
They WERE immortal before the fall.
ANIMALS and PLANTS were NOT. That is how evolution could have happened. Organisms were always dying. Its natural. But at first humans had a SUPERnatural existance. Then we lost it and reverted a great deal to our animal nature…and so died.