I hear a lot of " I woulds" Or " I plan to" and then some rationale for how the writer feels and why. I'm not sure those statement are realistic. The truth is, until you are in that space, you will have no idea what you will really feel/think/do.
I am just beginning to realize than I am either trans (most likely) or genderqueer (to say the least) and trying to put a name to something that I really am having a hard time coming to grips with myself. I also have two older teen sons. I think everyday about how will I tell them. As I am still in the initial stages I don't say anything, they have enough to deal with, with AP classes, looking at colleges, part time jobs, their own friends, and of course, trying to get girlfriends. It would be too much, and they would be too embarrassed to share this info or process it with their friends. It would "rock their world" and not in a good way.
I am not criticizing anyone on this board. I am just trying to put out that how we think we will act when a topic is abstract is often very different then how we feel about the topic when it is a reality, this goes for many things. As a nurse, I see families cope with end of life decisions, and they know that they should do, or "what mom would want", but when reality is at hand, it is entirely different, and more difficult decision.
There are also things that might play into your decision on when to tell or what to tell that are not even known to you right now. The decision may be influenced by where you are living, L.A. is different than Lubbock Texas. Or other things may come up that makes it important to tell, even if you hadn't plan on it.
I'm just saying, give yourself some wiggle room when you envision the future.