i think with a charizard u need sp atk or atk and speed, or sp atk and atk
so u need jolly for max speed, adamant for max atk and modest for max sp atk, i suggest adamant, for max atk and sp atk for the rest
so need to Ev it in atk, sp atk and a bit speed
EV spread: 252 on atk, 252 on sp atk, and 6 on speed(u may lower sp atk for speed if you prefer ur charizard faster)
give the charmander to daycare and take it back when its lvl 20
if you got power items put the one that boosts atk and kill 50 shinx when its holding the item, take the item back and beat 4 more shinx
make it hold the power item that boosts sp atk and kill 50 budew, and 4 more without the item
then beat 6 starly without holding any item
there are also faster and slower ways to do this, but i prefer this way, after doing this u can train the pokemon ANYWAY you want, it wont have an effect on its stats, dont worry
as for that shiny charmander u got, its pretty much useless since gentle boosts sp def, but i can give you a free shiny docile one(docile is neutral on all stats, better then gentle)
oh and, dont ask about this stuff in here anymore, go to help forums