Ok ok so I caught my first shiny in pokemon diamond?

For the past day I was chaining for a shiny starly because I wanted a staraptor for my team. When I saw the shiny patch I thought my eyes were mistaken...because the cahin was only at 30 which doesnt mean a too good of a chance but I took the risk, switched my adamant abra to try to ge tthe starly to be adamant. I found out it's naive. That gives a speed boost to staraptor's already high speed. Does this ruin the pokemon? Or is it still good...it's speD will be low because of the nature but idk, can anyone help is it still good in competitive battling? If so, is it still a good offensive sweeper? AND FINALLY MY FIRST SHINY EVER!!@#!@$#@^#$&^#