anon- yes, what you said about attending a university is correct. Those that choose that route end up more independent in the long run. Since for many people that is not an option, for whatever reason, seminary is a good second. It is not for everyone, but many I have known have matured, and they were quite mature to begin with! It is an experience being away from home. Yes, I had some of the same experiences you had, having to arrange with yomim tovim and the like- a very solidifying experience having to explain what the yom tov is about, do we really believe in “all that stuff”, ect. For those who go through it- kol hakovod in todays world, which is very different from years past. But at the same time, dont discount seminary. Would a girl I know, in secular college now, be able to go through it all without her sem experience? each experience is different and it depends on your sem and how your parents dealt with it.
You seem to have been quite mature to begin with. But for those who are not, and will not go to a secular college or even a frum one away from home, it is a bridge to “adulthood”.