I never built a PVC submarine at 12 I have played music by then though. Age isn't a major deal,, I mean you are 12,,,, I am 34,,, there are people that are 78 that do this and older., this is just a temporary situation we are going to a much better place. Don't listen to negitive people concerning your age. if that is what you have faced,. If you want to build one who cares how old you are just do it. only 4 years from now you will be driving!!! 4 years ain't much time in reality.. so 12 is old enough to embark on most things you could even drive right now if your parents allowing... go for it and don't worry about age,. I think you can build a sub as good as i can!!!!! or better. Good Luck and God bless