I played very little of valorant and I'm really bad. I panic when shooting and using my ability. What agent is easiest for begginers and how do I stop panicking?

It feels bad to kill a kayo in his ult form, have someone else shoot him while he is in the downed state, which then gives them the kill credit (and money). It's not a huge deal, I mean sharing is caring after all, but I'd still rather get...