Sounds like you think they might not be keen to the idea. You are 20, of age, hopefully with a job and taking care of all your affairs. You hopefully have a plan in mind for your future, too. I think it would be best for you to either get together with both sets of parents, like a dinner party or restaurant, and both you and your future spouse announce together, the engagement. If you are the girl, then in the old fashioned way, your boyfriend, can ask your parents blessing for your hand in marriage and if you are the boy, with the girl, you profess your love for her and impending engagement. There may be questions of "how will you"??? so be ready with solid answers that will make them feel better and included in your future plans.
You are a minor at 16 so marriage would be out of the question, but, you could be engaged legally as there is no law preventing that. The shock method to parents seldom works and if you both love each other and are mature for your years then a good suggestion is to have your fiance take your ring back from you; go see your parents and ask if he can become engaged to you, but that you both want to graduate and get your education before marriage. After you turn 18 you are free to do as you wish.
only when your boyfriend is there when there not then you can tell them all you want.
Tell your parents that you are ready to move on tell them that you dont want to do band, and your not good.
You just tell him
It's possible your fiance's parents may not want him to get married and would rather he is settled into his education; career before thinking of marriage. Communication is the key in any good relationship and it's time for you to sit down with your fiance and tell him that together you are going to tell his parents you are engaged. If he refuses then he's immature and if over 18 he is no longer a minor and should be able to make his own decisions and if he does refuse then give him the engagement ring back.
as long as you want to or as long as your parents tell you to
tell them you want to bring a friend
There is no formal Jewish custom, tradition, or law in this regard. But it makes sense in a way, that since the family unit is such an exceptionally strong infrastructure in a Jewish young person's maturation, if the newly-engaged couple are not totally estranged from their parents, then those are the first people they would want to tell.
Well do you need them or want them?
The best way to tell your parents you want to quit the cadets is to cit them down and explain what is going on. Many parents will understand completely.
Just tell your parents you want to be able to pretend you are camping in your room. Or, that you don't want to turn on lights when you need to walk to the bathroom at night.
Just ask your parents about dying your hair.
If your mom said that you can only see your boyfriend when his parents are home, you should honor that. If you don't want to, then just tell her they will be home, but this is wrong.