if you are gonna join the weightlifting team in high school there is gonna be weight classes.. so you must be as low weight as you can be and still be strong for your size if that makes sense.
i was in the 129 weight class in high school, hard to believe i was able to stay that trim but i was probably 5% bf.. we would run 45 minutes in 90 degree heat and workout 45 minutes 6X per week. and i knew to stay away from sweets, although my diet was substandard which is normal for a kid making minimim wage.
now if you want to be a strongman thats a different story, those guys eat everything that moves and they have high bf% compared to bodybuilders.. you won't win any bodybuilding competitions but you will be able to move cars lol. not the look i strive for but thats the sport of choice for many guys.
your best bet is to join your weightlifting team at school and hopefully you have a competent coach that can help you get to where you need to be.