Help getting in better shape?? Boxers needed!!?

so im thinking about trying girls boxing or kickboxing but i think i need to get in shape first. im about to go for my black belt in karate. i do karate 2 nights a week for a hour each and about 4 night a week i go on the punching bag and alternate that and speed rope and then weights for about 45 mins. im 13yrs old 5' 7" 150 lbs and i starrted taking vitamins and tonalin when i eat andve been doin this for a week or so.. will it work or any advice?