How does T'Challa have the spirit of the Black Panther during Civil War?

Question

In Captain America: Civil War, T'Challa takes the mantle of the Black Panther after his father is killed. As the Black Panther, he appears to have enhanced abilities.

In this interview with Collider, the Russos talk about T'Challa having superpowers and being enhanced during Civil War

JOE: It can absorb the energy, so it’s much harder to damage him as a character, and you can see that in the movie he can take a lot of punishment including bullets to the face. He is very well trained. He’s from one of the wealthiest countries on the planet, so there’s great infrastructure there; very technologically advanced country. So he’s been trained at the highest levels to fight, but he also has his own superpowers, which derive from the mythology of his nation. Those will be explored more in Black Panther, it’s clearly evident when he’s able to fight the Winter Soldier out of costume, and go toe-to-toe with him, that he is an enhanced individual.

In Black Panther, we see that in order to become the Black Panther,

one must imbibe juice from the heart-shaped flower and visit the spirit plane after being buried.

But before this,

T'Challa must have his Black Panther powers removed prior to the ritual combat challenge, which he does twice in the film.

This raises the question of how T'Challa could have possibly become the Black Panther abroad - or if he even really had.

How did Black Panther have his powers during Civil War?

Answer 1

Marvel published a prequel comic book to Black Panther, called Black Panther Prelude, that details the story of T'Challa becoming the Black Panther. His father chose to step down and pass on the mantle of Black Panther when it became clear he was too old to continue and his son was of age, ready and able to take over.

This happened sometime during the events of Iron Man, specifically about a week prior to the final scene in that movie where Tony Stark exposes his identity to the world. We see T'Chaka watching that on the news as he discusses a mission with the newly-annointed T'Challa.

So, by the time of Captain America: Civil War, T'Challa had already taken the heart-shaped herb, and had been the Black Panther for slightly less than a decade.

Answer 2

I can't comment so I apologize if the answer doesn't have proper sources (as of now).

I watched the movie on Wednesday. In the movie:

During the crowning ceremony once T'Challa is challenged, he breathes in the powder that neutralizes his enhanced abilities turning him into just a peak human. This implies that he had the spirit of the Black Panther for an unspecified amount of time before that, which includes the time during Civil War.

From what we have seen, it is likely that (in the MCU at least) the future king gets to practice being the Black Panther for some time before actually being crowned in order to prepare him for the challenges ahead.